PCI: xilinx-nwl: Rename the NWL_ECAM_VALUE_DEFAULT macro

Rename the NWL_ECAM_VALUE_DEFAULT macro to NWL_ECAM_MAX_SIZE and drop
the no longer needed ecam_value variable from struct nwl_pcie.

[kwilczynski: commit log]
Link: https://lore.kernel.org/linux-pci/20231016051102.1180432-4-thippeswamy.havalige@amd.com


Signed-off-by: Thippeswamy Havalige <thippeswamy.havalige@amd.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>