ALSA: ymfpci: fix PCM open error handling

The installation of the minimum period size constraint in the PCM open
callbacks was not checked for errors.  Add this check, and move the call
to the beginning of the function to avoid having to do any cleanups in
the error case.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>