staging: most: usb: move allocation of URB out of critical section

staging: most: usb: move allocation of URB out of critical section

This patch puts the call to usb_alloc_urb() before the critical
section starts that is protected with the io_mutex lock. This is
to make the section as short as possible and to use the regular
GFP_KERNEL flag.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/1590570387-27069-6-git-send-email-christian.gromm@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>