ALSA: compress: remove the sample rate check

commit f0e9c080 - "ALSA: compress: change the way sample rates are sent to
kernel" changed the way sample rates are sent. So now we don't need to check for
PCM_RATE_xxx in kernel

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>