drm/amdgpu: add flag to support IH clock gating

Add new flag for IH (interrupt handler) clockgating.
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/include/amd_shared.h

@@ -95,6 +95,7 @@ enum amd_powergating_state {
 #define AMD_CG_SUPPORT_VCN_MGCG			(1 << 24)
 #define AMD_CG_SUPPORT_HDP_DS			(1 << 25)
 #define AMD_CG_SUPPORT_HDP_SD			(1 << 26)
+#define AMD_CG_SUPPORT_IH_CG			(1 << 27)
 /* PG flags */
 #define AMD_PG_SUPPORT_GFX_PG			(1 << 0)
 #define AMD_PG_SUPPORT_GFX_SMG			(1 << 1)