Fix the __init/__exit annotations

Fix the __init/__exit annotations

WARNING: drivers/media/video/cx18/cx18-alsa.o(.text+0x4de): Section
mismatch in reference from the function cx18_alsa_load() to the function
.init.text:snd_cx18_init()
The function cx18_alsa_load() references
the function __init snd_cx18_init().
This is often because cx18_alsa_load lacks a __init
annotation or the annotation of snd_cx18_init is wrong.

WARNING: drivers/media/video/cx18/built-in.o(.text+0x1c022): Section
mismatch in reference from the function cx18_alsa_load() to the function
.init.text:snd_cx18_init()
The function cx18_alsa_load() references
the function __init snd_cx18_init().
This is often because cx18_alsa_load lacks a __init
annotation or the annotation of snd_cx18_init is wrong.

WARNING: drivers/media/video/built-in.o(.text+0x28cc56): Section
mismatch in reference from the function cx18_alsa_load() to the function
.init.text:snd_cx18_init()
The function cx18_alsa_load() references
the function __init snd_cx18_init().
This is often because cx18_alsa_load lacks a __init
annotation or the annotation of snd_cx18_init is wrong.

WARNING: drivers/media/built-in.o(.text+0x2d2432): Section mismatch in
reference from the function cx18_alsa_load() to the function
.init.text:snd_cx18_init()
The function cx18_alsa_load() references
the function __init snd_cx18_init().
This is often because cx18_alsa_load lacks a __init
annotation or the annotation of snd_cx18_init is wrong.

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