Input: mtk-pmic-keys - allow compiling with COMPILE_TEST

There are no hard architecture dependencies in the driver, so to improve
compile test coverage let's enable the driver when COMPILE_TEST is
selected.

Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/YowG7BVsJTNd0ELi@google.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/Kconfig

@@ -795,7 +795,7 @@ config KEYBOARD_MT6779
 
 config KEYBOARD_MTK_PMIC
 	tristate "MediaTek PMIC keys support"
-	depends on MFD_MT6397
+	depends on MFD_MT6397 || COMPILE_TEST
 	help
 	  Say Y here if you want to use the pmic keys (powerkey/homekey).