add edc counter/status reset and query functions for gfx block of
aldebaran.

v2: change to clear edc counter explicitly
aldebaran hardware will not clear edc counter after driver reading them,
so driver should clear them explicitly.
Signed-off-by: Dennis Li <Dennis.Li@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>