pci: Enable PCI_MAP_SYSTEM_MEMORY when ARCH_MAP_SYSMEM is not set

For MIPS we are always looking gd->dram in virtual address so
PCI_MAP_SYSTEM_MEMORY should always be enabled.

If in future we ever want to make it physical we have to set
ARCH_MAP_SYSMEM.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
1 file changed