linux-phytec-ti

ALSA: compress: Add SNDRV_PCM_STATE_PREPARED state explanation

Stream states were explained in the code comments but
SNDRV_PCM_STATE_PREPARED was missed so add it

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