media: vivid: remove redundant assignment to variable checksum

Variable checksum is assigned a value that is never read, it is assigned
a new value in a following for-loop. The assignment is redundant and can
be removed.

Cleans up clang scan build warning:
drivers/media/test-drivers/vivid/vivid-vbi-gen.c:197:2: warning: Value
stored to 'checksum' is never read [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: media/test_drivers: rename to test-drivers

We never use _ in directory names in the media subsystem, so
rename to test-drivers instead for consistency.

Also update MAINTAINERS with the new path.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>