[ALSA] Fix-up sleeping in sound/usb

USB generic driver,USB USX2Y
Description: Fix-up sleeping in sound/usb. Replace big_mdelay() with
msleep() to guarantee the task delays as expected. This also involved
replacing/removing custom sleep functions.

Patch is compile-tested.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>