drm/radeon: add gpu init support for CIK (v9)

v2: tiling fixes
v3: more tiling fixes
v4: more tiling fixes
v5: additional register init
v6: rebase
v7: fix gb_addr_config for KV/KB
v8: drop wip KV bits for now, add missing config reg
v9: fix cu count on Bonaire

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>