drm/amd/powerplay: Fix enum mismatch

commit 42b5122e828a6ccd9952ad3116343dc032d33efe upstream.

In several locations the driver uses AMD_CG_STATE_UNGATE (type enum
amd_clockgating_state) instead of AMD_PG_STATE_UNGATE (type enum
amd_powergating_stat) and vice versa. Both constants have the same
value, so this doesn't cause any problems, but we still want to pass
the correct type.

Fixing the mismatch resolves multiple warnings like this when building
with clang:

drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/cz_clockpowergating.c:169:7:
  error: implicit conversion from enumeration type 'enum
  amd_powergating_state' to different enumeration type 'enum
  amd_clockgating_state' [-Werror,-Wenum-conversion]
    AMD_PG_STATE_UNGATE);

Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>