spi: spi-pci1xxxx: Drop MSI-X usage as unsupported by DMA engine

Removes MSI-X from the interrupt request path, as the DMA engine used by
the SPI controller does not support MSI-X interrupts.

Signed-off-by: Thangaraj Samynathan <thangaraj.s@microchip.com>
Link: https://patch.msgid.link/20250612023059.71726-1-thangaraj.s@microchip.com


Signed-off-by: Mark Brown <broonie@kernel.org>