usb: gadget: r8a66597-udc: do not unlock unheld spinlock in r8a66597_sudmac_irq()

r8a66597_irq() processes sudmac part (r8a66597_sudmac_irq()) before locking r8a66597->lock.
But transfer_complete(), that is called inside (r8a66597_sudmac_irq()->sudmac_finish()->transfer_complete()),
expects r8a66597->lock is locked. As a result unheld spinlock can be unlocked.

The patch just moves locking before calling r8a66597_sudmac_irq().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Felipe Balbi <balbi@ti.com>