PCI: microchip: Correct the DED and SEC interrupt bit offsets

PCI: microchip: Correct the DED and SEC interrupt bit offsets

The SEC and DED interrupt bits are laid out the wrong way round so the SEC
interrupt handler attempts to mask, unmask, and clear the DED interrupt
and vice versa. Correct the bit offsets so that each interrupt handler
operates properly.

Link: https://lore.kernel.org/r/20230728131401.1615724-2-daire.mcnamara@microchip.com
Fixes: 6f15a9c9f941 ("PCI: microchip: Add Microchip PolarFire PCIe controller driver")
Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>