media: bt8xx: Remove unnecessary self-assignment

Clang warns when a variable is assigned to itself.

drivers/media/pci/bt8xx/bttv-driver.c:2043:13: warning: explicitly
assigning value of variable of type '__s32' (aka 'int') to itself
[-Wself-assign]
        min_height = min_height;
        ~~~~~~~~~~ ^ ~~~~~~~~~~
1 warning generated.

There doesn't appear to be any good reason for this and this statement
was added in commit e5bd0260 ("V4L/DVB (5077): Bttv cropping
support") back in 2007. Just remove it.

Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>