linux-phytec-ti

drm/radeon: fixup bad vram size on SI

Some boards seem to have garbage in the upper
16 bits of the vram size register.  Check for
this and clamp the size properly.  Fixes
boards reporting bogus amounts of vram.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org