video: fbdev: uvesafb: Fix set but not used warning

Fix W=1 warning by deleting unused local variable.

v2:
  - Updated subject (Lee)

v3:
  - Return early in case of an error (Thomas)

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Michal Januszewski <spock@gentoo.org>
Cc: linux-fbdev@vger.kernel.org
Cc: Lee Jones <lee.jones@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201206190247.1861316-5-sam@ravnborg.org

drivers/video/fbdev/uvesafb.c

@@ -560,6 +560,8 @@ static int uvesafb_vbe_getpmi(struct uvesafb_ktask *task,
 	task->t.regs.eax = 0x4f0a;
 	task->t.regs.ebx = 0x0;
 	err = uvesafb_exec(task);
+	if (err)
+		return err;
 
 	if ((task->t.regs.eax & 0xffff) != 0x4f || task->t.regs.es < 0xc000) {
 		par->pmi_setpal = par->ypan = 0;