[ALSA] fix compilation warning in GCC

'snd_shutdown_f_ops' is not a pointer so its address will never be NULL.
GCC will complain because 'fops_get' will do an unnecessary check because
'&snd_shutdown_f_ops' is always true.

Signed-off-by: Miguel Boton <mboton@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>