media: exynos4-is: Fix compile warning

stable inclusion
from stable-v5.10.121
commit 86c02171bded33534e418c66320dfd930fda62b3
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6CQ

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=86c02171bded33534e418c66320dfd930fda62b3

--------------------------------

[ Upstream commit e080f5c1 ]

Declare static on function 'fimc_isp_video_device_unregister'.

When VIDEO_EXYNOS4_ISP_DMA_CAPTURE=n, compiler warns about
warning: no previous prototype for function [-Wmissing-prototypes]
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NKwanghoon Son <k.son@samsung.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/media/platform/exynos4-is/fimc-isp-video.h

@@ -32,7 +32,7 @@ static inline int fimc_isp_video_device_register(struct fimc_isp *isp,
 	return 0;
 }
 
-void fimc_isp_video_device_unregister(struct fimc_isp *isp,
+static inline void fimc_isp_video_device_unregister(struct fimc_isp *isp,
 				enum v4l2_buf_type type)
 {
 }