mailbox: client-cdev: Fix unmap warning when remove the driver

The memory region is mapped using devm_ioremap_wc. but the unmap is
done in the probe in case of error or on remove.
This lead to a warning:
[  860.695243] Trying to vunmap() nonexistent vm area (00000000424aa509)
[  860.703967] WARNING: CPU: 0 PID: 1194 at mm/vmalloc.c:2888 vunmap+0x58/0x60
[  860.708640] Modules linked in: cfg80211 rfkill usb_f_ncm u_ether crct10dif_ce hantro_vpu imx335 libcomposite stm32_dcmipp v4l2_jpeg v4l2_vp9 stm32_csi v4l2_h264 v4l2_mem2mem videobuf2_vm6
[  860.746428] CPU: 0 PID: 1194 Comm: sh Not tainted 6.6.48 torvalds#170
[  860.752164] Hardware name: STMicroelectronics STM32MP257F-EV1 Evaluation Board (DT)
[  860.759803] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  860.766742] pc : vunmap+0x58/0x60
[  860.770069] lr : vunmap+0x58/0x60
[  860.773293] sp : ffff800082a83af0
[  860.776613] x29: ffff800082a83af0 x28: ffff000081c38ec0 x27: 0000000000000000
[  860.783759] x26: 0000000000000000 x25: 0000000000000000 x24: ffff0000803be010
[  860.790804] x23: 0000000000000002 x22: ffff800082a83b38 x21: ffff0000803be010
[  860.797950] x20: ffff000082ae4000 x19: ffff80008224a000 x18: 0000000000000000
[  860.805095] x17: 0000000000000000 x16: 0000000000000000 x15: 0072994003df956c
[  860.812140] x14: 00001ca45e4a1b34 x13: 000000000000018e x12: 000000000000018e
[  860.819285] x11: 0000000000000000 x10: 0000000000000a60 x9 : ffff800082a83960
[  860.826330] x8 : ffff000081c39980 x7 : ffff0000ff76fe00 x6 : 0000000000729940
[  860.833476] x5 : 00000000410fd040 x4 : 0000000000100000 x3 : 0000000000000000
[  860.840520] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000081c38ec0
[  860.847666] Call trace:
[  860.850083]  vunmap+0x58/0x60
[  860.853007]  iounmap+0x30/0x3c
[  860.856030]  devm_ioremap_release+0x14/0x20
[  860.860259]  devres_release_all+0xa4/0x10c
[  860.864290]  device_unbind_cleanup+0x18/0x68
[  860.868521]  device_release_driver_internal+0x1e8/0x224
[  860.873753]  device_links_unbind_consumers+0xd8/0x100
[  860.878786]  device_release_driver_internal+0xe0/0x224
[  860.883917]  device_driver_detach+0x18/0x24

Remove useless iounmap

Fixes: a2435dc ("mailbox: Add mailbox character device driver for coprocessor communication")

Change-Id: Iaff88eef53f9e900e0d8758be6ef45df45c61bab
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/linux-stm32/+/426869
Domain-Review: Arnaud POULIQUEN <arnaud.pouliquen@st.com>
Reviewed-by: Gwenael TREUVEUR <gwenael.treuveur@st.com>
Reviewed-by: Arnaud POULIQUEN <arnaud.pouliquen@st.com>
Tested-by: Arnaud POULIQUEN <arnaud.pouliquen@st.com>
ACI: CITOOLS <MDG-smet-aci-reviews@list.st.com>
ACI: CIBUILD <MDG-smet-aci-builds@list.st.com>

Author: arnopo

drivers/mailbox/mailbox-client_cdev.c

@@ -211,7 +211,6 @@ static void mbox_cdev_driver_remove(struct platform_device *pdev)
 	struct mbox_cdev_ddata *mbxdev = platform_get_drvdata(pdev);
 
 	mbox_free_channel(mbxdev->mb.chan);
-	iounmap(mbxdev->resm);
 	cdev_del(&mbxdev->cdev);
 }
 
@@ -234,7 +233,7 @@ static int mbox_cdev_driver_probe(struct platform_device *pdev)
 	/* Initialize mailbox client */
 	ret = mbox_cdev_request_mbox(dev, mbxdev);
 	if (ret)
-		goto unmap;
+		return ret;
 
 	ret = mbxdev_char_device_add(pdev, mbxdev);
 	if (ret)
@@ -246,8 +245,6 @@ static int mbox_cdev_driver_probe(struct platform_device *pdev)
 
 free_mbx:
 	mbox_free_channel(mbxdev->mb.chan);
-unmap:
-	iounmap(mbxdev->resm);
 
 	return ret;
 }