[ALSA] PCM core - remove SNDRV_PCM_TSTAMP_MMAP condition in snd_pcm_status()

The condition caused that the returned ring buffer position does not match
with timestamp when SNDRV_PCM_TSTAMP_MMAP mode was enabled. Removing
condition makes unified behaviour and interrupt based timestamp can be
accessed via PCM_IOCTL_SYNC_PTR or mmaped status area.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>