V4L/DVB: Staging: cx25821: fix coding style issues in cx25821-alsa.c

>From 9473816c446a6ca91905fc49a73732f70b5223b4 Mon Sep 17 00:00:00 2001
 This is a patch to the cx25821-alsa.c file that fixes up errors and warnings found by the checkpatch.pl tool

[mchehab@redhat.com: a few adjustments on the comments to improve readability]
Signed-off-by: Olimpiu Pascariu <olimpiu.pascariu@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>