drm/amd/display: Cap pflip irqs per max otg number

[Why]
pflip interrupt order are mapped 1 to 1 to otg id.
e.g. if irq_src=26 corresponds to otg0 then 27->otg1, 28->otg2...

Linux DM registers pflip interrupts per number of crtcs.
In fused pipe case crtc numbers can be less than otg id.

e.g. if one pipe out of 3(otg#0-2) is fused adev->mode_info.num_crtc=2
so DM only registers irq_src 26,27.
This is a bug since if pipe#2 remains unfused DM never gets
otg2 pflip interrupt (irq_src=28)
That may results in gfx failure due to pflip timeout.

[How]
Register pflip interrupts per max num of otg instead of num_crtc
Signed-off-by: Roman Li <Roman.Li@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -3653,7 +3653,7 @@ static int dcn10_register_irq_handlers(struct amdgpu_device *adev)
 
 	/* Use GRPH_PFLIP interrupt */
 	for (i = DCN_1_0__SRCID__HUBP0_FLIP_INTERRUPT;
-			i <= DCN_1_0__SRCID__HUBP0_FLIP_INTERRUPT + adev->mode_info.num_crtc - 1;
+			i <= DCN_1_0__SRCID__HUBP0_FLIP_INTERRUPT + dc->caps.max_otg_num - 1;
 			i++) {
 		r = amdgpu_irq_add_id(adev, SOC15_IH_CLIENTID_DCE, i, &adev->pageflip_irq);
 		if (r) {

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -1220,6 +1220,8 @@ struct dc *dc_create(const struct dc_init_data *init_params)
 
 		dc->caps.max_dp_protocol_version = DP_VERSION_1_4;
 
+		dc->caps.max_otg_num = dc->res_pool->res_cap->num_timing_generator;
+
 		if (dc->res_pool->dmcu != NULL)
 			dc->versions.dmcu_version = dc->res_pool->dmcu->dmcu_version;
 	}

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

@@ -202,6 +202,7 @@ struct dc_caps {
 	bool edp_dsc_support;
 	bool vbios_lttpr_aware;
 	bool vbios_lttpr_enable;
+	uint32_t max_otg_num;
 };
 
 struct dc_bug_wa {