b43: Fix resume failure

This fixes a resume failure where a signal is pending on resume
so the firmware upload fails.
This removes the interruptible sleep, because we don't really need it.
In the worst case (with broken firmware) the sleep loop will take 1 second.
In the common case (working firmware), it will only take a few milliseconds.
So we don't really need to be interruptible.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>