drm/radeon/kms: fix tiling info on evergreen

We aren't currently using tiling in userspace on evergreen,
but the info we currently return for the tiling info query
(gb_addr_config) is no adequate for userspace tiling alignment
calculations.  It does not contain the bank info.  Create a custom
tiling info dword with all the necessary info (num channels,
num banks, group size, row size).

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>