We were testing the register offset, instead of the value stored in the
register, therefore always timing out the loop.

This reduces suspend time of the system in the bug report below by ~600
ms.

Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/107277Tested-by: NPaul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NJunwei Zhang <Jerry.Zhang@amd.com>
Signed-off-by: NMichel Dänzer <michel.daenzer@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>