[ALSA] usbaudio - Revert the minimal period size fix patch

The last patch didn't really work (false report).
Although the hardware supports 125us minimum period, the current
usb-audio driver code assumes the 1ms period in many places.
Rollback the change.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>