media: MAINTAINERS: update videobuf2 entry

Commits 03fbdb2fc2 ("media: move videobuf2 to drivers/media/common")
and 7952be9b6e ("media: drivers/media/common/videobuf2: rename from
videobuf") moved videobuf2 framework source code finally to
drivers/media/common/videobuf2 directory, so update relevant paths in
MAINTAINERS file.

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

MAINTAINERS

@@ -15479,7 +15479,7 @@ M:	Marek Szyprowski <m.szyprowski@samsung.com>
 M:	Kyungmin Park <kyungmin.park@samsung.com>
 L:	linux-media@vger.kernel.org
 S:	Maintained
-F:	drivers/media/v4l2-core/videobuf2-*
+F:	drivers/media/common/videobuf2/*
 F:	include/media/videobuf2-*
 
 VIMC VIRTUAL MEDIA CONTROLLER DRIVER