PCI: meson: Fix parsing the DBI register region

PCI: meson: Fix parsing the DBI register region

First of all, the driver was parsing the 'dbi' register region as 'elbi'.
This was due to DT mistakenly passing 'dbi' as 'elbi'. Since the DT is
now fixed to supply 'dbi' region, this driver can rely on the DWC core
driver to parse and map it.

However, to support the old DTs, if the 'elbi' region is found in DT, parse
and map the region as both 'dw_pcie::elbi_base' as 'dw_pcie::dbi_base'.
This will allow the driver to work with both broken and fixed DTs.

Also, skip parsing the 'elbi' region in DWC core if 'pci->elbi_base' was
already populated.

Fixes: 9c0ef6d34fdb ("PCI: amlogic: Add the Amlogic Meson PCIe controller driver")
Fixes: c96992a24bec ("PCI: dwc: Add support for ELBI resource mapping")
Reported-by: Linnaea Lavia <linnaea-von-lavia@live.com>
Closes: https://lore.kernel.org/linux-pci/DM4PR05MB102707B8CDF84D776C39F22F2C7F0A@DM4PR05MB10270.namprd05.prod.outlook.com/
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on Bananapi-M2S
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Cc: stable@vger.kernel.org # 6.2
Link: https://patch.msgid.link/20251101-pci-meson-fix-v1-3-c50dcc56ed6a@oss.qualcomm.com