drm/amd/pm: always allow ih interrupt from fw

always allow ih interrupt from fw on smu v14 based on
the interface requirement

Signed-off-by: Kenneth Feng <kenneth.feng@amd.com>
Reviewed-by: Yang Wang <kevinyang.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>