usb: gadget: mv_u3d: request_irq() after initializing UDC

usb: gadget: mv_u3d: request_irq() after initializing UDC

If IRQ occurs between calling  request_irq() and  mv_u3d_eps_init(),
then null pointer dereference occurs since u3d->eps[] wasn't
initialized yet but used in mv_u3d_nuke().

The patch puts registration of the interrupt handler after
initializing of neccesery data.

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

Fixes: 90fccb529d24 ("usb: gadget: Gadget directory cleanup - group UDC drivers")
Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Nadezda Lutovinova <lutovinova@ispras.ru>
Link: https://lore.kernel.org/r/20210818141247.4794-1-lutovinova@ispras.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>