PCI: xilinx-cpm: Move IRQ definitions to a common header

Move the interrupt bit definitions to the pcie-xilinx-common.h file,
which then can be shared between pcie-xilinx-cpm and the new xilinx-xdma
drivers.

While at it, also rename them so these definitions are not CPM-specific.

No functional change intended.

[kwilczynski: commit log]
Link: https://lore.kernel.org/linux-pci/20231003173453.938190-2-thippeswamy.havalige@amd.com
Signed-off-by: Thippeswamy Havalige <thippeswamy.havalige@amd.com>
Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@amd.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>