drm/i915/mtl: Re-use ADL-P's "DC off" power well

As with ADL-P, MTL's "DC off" power well should be a dependency of the
PGC and PGD power wells, not the entire PG2 well. In fact, the DC5/DC6
requirements between the two platforms are the same, so the Xe_LPD "DC
off" well definition can just be re-used for Xe_LPD+.

Bspec: 49193
Signed-off-by: Matt Roper <[e-mail]>
Signed-off-by: Radhakrishna Sripada <[e-mail]>
Reviewed-by: Imre Deak <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/display/intel_display_power_map.c

···
 	XELPDP_PW_2_POWER_DOMAINS,
 	POWER_DOMAIN_INIT);
 
-I915_DECL_PW_DOMAINS(xelpdp_pwdoms_dc_off,
-	XELPDP_PW_2_POWER_DOMAINS,
-	POWER_DOMAIN_AUDIO_MMIO,
-	POWER_DOMAIN_MODESET,
-	POWER_DOMAIN_AUX_A,
-	POWER_DOMAIN_AUX_B,
-	POWER_DOMAIN_DC_OFF,
-	POWER_DOMAIN_INIT);
-
 I915_DECL_PW_DOMAINS(xelpdp_pwdoms_aux_tc1,
 	POWER_DOMAIN_AUX_USBC1,
 	POWER_DOMAIN_AUX_TBT1);
···
 
 static const struct i915_power_well_desc xelpdp_power_wells_main[] = {
 	{
-		.instances = &I915_PW_INSTANCES(
-			I915_PW("DC_off", &xelpdp_pwdoms_dc_off,
-				.id = SKL_DISP_DC_OFF),
-		),
-		.ops = &gen9_dc_off_power_well_ops,
-	}, {
 		.instances = &I915_PW_INSTANCES(
 			I915_PW("PW_2", &xelpdp_pwdoms_pw_2,
 				.hsw.idx = ICL_PW_CTL_IDX_PW_2,
···
 static const struct i915_power_well_desc_list xelpdp_power_wells[] = {
 	I915_PW_DESCRIPTORS(i9xx_power_wells_always_on),
 	I915_PW_DESCRIPTORS(icl_power_wells_pw_1),
+	I915_PW_DESCRIPTORS(xelpd_power_wells_dc_off),
 	I915_PW_DESCRIPTORS(xelpdp_power_wells_main),
 };