media: omap4iss: make it build with COMPILE_TEST

This driver compile as-is with COMPILE_TEST.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/staging/media/omap4iss/Kconfig

 config VIDEO_OMAP4
 	tristate "OMAP 4 Camera support"
-	depends on VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API && I2C && ARCH_OMAP4
+	depends on VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API && I2C
+	depends on ARCH_OMAP4 || COMPILE_TEST
 	depends on HAS_DMA
 	select MFD_SYSCON
 	select VIDEOBUF2_DMA_CONTIG