PCI: microchip: Enable event handlers to access bridge and control pointers

Minor re-organisation so that event handlers can access both a pointer
to the bridge area of the PCIe Root Port and the control area of the PCIe
Root Port.

Link: https://lore.kernel.org/r/20230728131401.1615724-5-daire.mcnamara@microchip.com


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>