drm/amdgpu: workaround the TMR MC address issue (v2)

With the 2-level gart page table,  vram is squeezed into gart aperture
and FB aperture is disabled. Therefore all VRAM virtual addresses are
 in the GART aperture. However currently PSP requires TMR addresses
in FB aperture. So we need some design change at PSP FW level to support
this 2-level gart table driver change. Right now this PSP FW support
doesn't exist. To workaround this issue temporarily, FB aperture is
added back and the gart aperture address is converted back to FB aperture
for this PSP TMR address.

Will revert it after we get a fix from PSP FW.

v2: squash in tmr fix for other asics (Kevin)

Signed-off-by: Oak Zeng <Oak.Zeng@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>