media: lmedm04: remove redundant assignment to variable gate

The variable gate is being initialized and also checked and re-assigned
with values that are never read as it is being re-assigned later in a
for-loop with a new value.  The assignments are redundant and can be
removed.

Addresses Coverity ("Unused value")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>