arm64: dts: qcom: sc7280: Increase config size to 256MB for ECAM feature

arm64: dts: qcom: sc7280: Increase config size to 256MB for ECAM feature

PCIe ECAM(Enhanced Configuration Access Mechanism) feature requires
maximum of 256MB configuration space.

To enable this feature increase configuration space size to 256MB. If
the config space is increased, the BAR space needs to be truncated as
it resides in the same location. To avoid the bar space truncation move
config space, DBI, ELBI, iATU to upper PCIe region and use lower PCIe
iregion entirely for BAR region.

This depends on the commit: '10ba0854c5e6 ("PCI: qcom: Disable mirroring
of DBI and iATU register space in BAR region")'

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250828-ecam_v4-v8-1-92a30e0fa02d@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>