[media] allow COMPILE_TEST for SAMSUNG_EXYNOS4_IS

That helps some static checks, so enable it. While there, it was
noticed that linux/sizes.h was missing:

drivers/media/platform/exynos4-is/mipi-csis.c: In function ‘s5pcsis_s_rx_buffer’:
drivers/media/platform/exynos4-is/mipi-csis.c:114:31: error: ‘SZ_4K’ undeclared (first use in this function)
 #define S5PCSIS_PKTDATA_SIZE  SZ_4K
                               ^
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/platform/exynos4-is/Kconfig

@@ -2,7 +2,7 @@
 config VIDEO_SAMSUNG_EXYNOS4_IS
 	bool "Samsung S5P/EXYNOS4 SoC series Camera Subsystem driver"
 	depends on VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
-	depends on (PLAT_S5P || ARCH_EXYNOS)
+	depends on (PLAT_S5P || ARCH_EXYNOS || COMPILE_TEST)
 	depends on OF && COMMON_CLK
 	help
 	  Say Y here to enable camera host interface devices for

drivers/media/platform/exynos4-is/mipi-csis.c

@@ -25,6 +25,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
+#include <linux/sizes.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/videodev2.h>