drm/amdgpu: Use gmc->noretry instead of amdgpu_noretry directly

drm/amdgpu: Use gmc->noretry instead of amdgpu_noretry directly

Whether retry faults are actually enabled, is determined by
the amdgpu_gmc_noretry_set() function. The rest of the code
base should use gmc->noretry instead of the module parameter.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>