Add patch for spi-xilinx driver to allow optional IRQ

[domingo-nexthop]

Upstream patch accepted in linux next: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/spi/spi-xilinx.c?h=next-20260204&id=c3608162a95a259c669cf9fdccf900782fa8d902