V4L/DVB (10525): em28xx: Coding style fixes and a typo correction

Lots of coding style fixes and a typo correction for em28xx.

[dougsland@redhat.com: fixed a reject due to a change on em28xx-audio.c]
Signed-off-by: Nicola Soranzo <nsoranzo@tiscali.it>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>