Staging: cx25821: Replace :? by if-else in cx25821-video.c

Replace :? operator by equivalent if-else statement where in improves
readability. Don't add else branch if it is not needed.

Signed-off-by: Leonid V. Fedorenchik <leonidsbox@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>