drm/amdgpu: Reorder to read EFI exported ROM first

drm/amdgpu: Reorder to read EFI exported ROM first

On EFI BIOSes, PCI ROM may be exported through EFI_PCI_IO_PROTOCOL and
expansion ROM BARs may not be enabled. Choose to read from EFI exported
ROM data before reading PCI Expansion ROM BAR.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>