drm/amd/display: Extend soc BB capabilitiy

[why]
Some parts are consuming dangerously close to maximum number of states
supported when updating the BB (i.e. 8).

[how]
Change maximum stages from 9 to 20.
Reviewed-by: Alvin Lee <Alvin.Lee2@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Jun Lei <jun.lei@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dc.h

@@ -747,6 +747,7 @@ struct dc_debug_options {
 	union aux_wake_wa_options aux_wake_wa;
 	uint8_t psr_power_use_phy_fsm;
 	enum dml_hostvm_override_opts dml_hostvm_override;
+	bool use_legacy_soc_bb_mechanism;
 };
 
 struct gpu_info_soc_bounding_box_v1_0;

drivers/gpu/drm/amd/display/dc/dml/dc_features.h

@@ -29,7 +29,7 @@
 #define DC__PRESENT 1
 #define DC__PRESENT__1 1
 #define DC__NUM_DPP 4
-#define DC__VOLTAGE_STATES 9
+#define DC__VOLTAGE_STATES 20
 #define DC__NUM_DPP__4 1
 #define DC__NUM_DPP__0_PRESENT 1
 #define DC__NUM_DPP__1_PRESENT 1