Input: imx_keypad - add COMPILE_TEST support

Add COMPILE_TEST support to imx_keypad driver for better compile
testing coverage.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1583137573-16628-1-git-send-email-Anson.Huang@nxp.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/Kconfig

@@ -457,7 +457,7 @@ config KEYBOARD_SNVS_PWRKEY
 
 config KEYBOARD_IMX
 	tristate "IMX keypad support"
-	depends on ARCH_MXC
+	depends on ARCH_MXC || COMPILE_TEST
 	select INPUT_MATRIXKMAP
 	help
 	  Enable support for IMX keypad port.