[media] flexcop: CodingStyle fix: don't use "if ((ret = foo()) < 0)"

Lift assignments from "if" conditionals for readability.  No change
in functionality intended.

Suggested-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>