USB: fsl_qe_udc: Fix recursive locking bug in ch9getstatus()

USB: fsl_qe_udc: Fix recursive locking bug in ch9getstatus()

The call chain is this:

qe_udc_irq() <- grabs the udc->lock spinlock
rx_irq()
qe_ep0_rx()
ep0_setup_handle()
setup_received_handle()
ch9getstatus()
qe_ep_queue() <- tries to grab the udc->lock again

It seems unsafe to temporarily drop the lock in the ch9getstatus(),
so to fix that bug the lock-less __qe_ep_queue() function
implemented and used by the ch9getstatus().

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>