media: cec_gpio: allow building CEC_GPIO with COMPILE_TEST

At least on i386, building with allyesconfig doesn't enable
PREEMPT, causing cec_gpio to not build.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/Kconfig

@@ -558,7 +558,7 @@ config VIDEO_MESON_AO_CEC
 
 config CEC_GPIO
 	tristate "Generic GPIO-based CEC driver"
-	depends on PREEMPT
+	depends on PREEMPT || COMPILE_TEST
 	select CEC_CORE
 	select CEC_PIN
 	select GPIOLIB