rtlwifi: Don't block interrupts in spinlocks

Now power state transitions are not called from an
interrupt context, there's no need to block interrupts.

This code appears to block interrupts for too long,
causing my trackpad to lose sync occasionally.

Signed-off-by: Mike McCormack <mikem@ring3k.org>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>