iio: magnetometer: yas530: Add YAS537 variant

Add support for the magnetometer Yamaha YAS537. The additions are based on
comparison of Yamaha Android kernel drivers for YAS532 [1] and YAS537 [2].

In the Yamaha YAS537 Android driver, there is an overflow/underflow control
implemented. For regular usage, this seems not necessary. A similar overflow/
underflow control of Yamaha YAS530/532 Android driver isn't integrated in the
mainline driver. It is therefore skipped for YAS537 in the mainline too.

Also in the Yamaha YAS537 Android driver, at the end of the reset_yas537()
function, a measurement is saved in "last_after_rcoil". Later on, this is
compared to current measurements. If the difference gets too big, a new
reset is initialized. The difference in measurements needs to be quite big,
it's hard to say if this is necessary for regular operation. Therefore this
isn't integrated in the mainline driver either.

[1] https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas532.c
[2] https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas537.c

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/264c6488733a5c32089c9ab406a5bcb808c48fef.1660337264.git.jahau@rocketmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/magnetometer/Kconfig

@@ -216,8 +216,8 @@ config YAMAHA_YAS530
 	select IIO_TRIGGERED_BUFFER
 	help
 	  Say Y here to add support for the Yamaha YAS530 series of
-	  3-Axis Magnetometers. Right now YAS530, YAS532 and YAS533 are
-	  fully supported.
+	  3-Axis Magnetometers. YAS530, YAS532, YAS533 and YAS537 are
+	  supported.
 
 	  This driver can also be compiled as a module.
 	  To compile this driver as a module, choose M here: the module