drm/radeon: Fix vram_size/visible values in DRM_RADEON_GEM_INFO ioctl

drm/radeon: Fix vram_size/visible values in DRM_RADEON_GEM_INFO ioctl

commit 51964e9e12d0a054002a1a0d1dec4f661c7aaf28 upstream.

vram_size is supposed to be the total amount of VRAM that can be used by
userspace, which corresponds to the TTM VRAM manager size (which is
normally the full amount of VRAM, but can be just the visible VRAM when
DMA can't be used for BO migration for some reason).

The above was incorrectly used for vram_visible before, resulting in
generally too large values being reported.

Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>