drm/amd/display: Remove register from DCN35 DMCUB diagnostic collection

[ Upstream commit 466423c ]

[Why]
These registers should not be read from driver and triggering the
security violation when DMCUB work times out and diagnostics are
collected blocks Z8 entry.

[How]
Remove the register read from DCN35.

Reviewed-by: Duncan Ma <duncan.ma@amd.com>
Acked-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Nicholas Kazlauskas

drivers/gpu/drm/amd/display/dmub/src/dmub_dcn35.c

@@ -459,7 +459,7 @@ uint32_t dmub_dcn35_get_current_time(struct dmub_srv *dmub)
 void dmub_dcn35_get_diagnostic_data(struct dmub_srv *dmub, struct dmub_diagnostic_data *diag_data)
 {
 	uint32_t is_dmub_enabled, is_soft_reset, is_sec_reset;
-	uint32_t is_traceport_enabled, is_cw0_enabled, is_cw6_enabled;
+	uint32_t is_traceport_enabled, is_cw6_enabled;
 
 	if (!dmub || !diag_data)
 		return;
@@ -510,9 +510,6 @@ void dmub_dcn35_get_diagnostic_data(struct dmub_srv *dmub, struct dmub_diagnosti
 	REG_GET(DMCUB_CNTL, DMCUB_TRACEPORT_EN, &is_traceport_enabled);
 	diag_data->is_traceport_en  = is_traceport_enabled;
 
-	REG_GET(DMCUB_REGION3_CW0_TOP_ADDRESS, DMCUB_REGION3_CW0_ENABLE, &is_cw0_enabled);
-	diag_data->is_cw0_enabled = is_cw0_enabled;
-
 	REG_GET(DMCUB_REGION3_CW6_TOP_ADDRESS, DMCUB_REGION3_CW6_ENABLE, &is_cw6_enabled);
 	diag_data->is_cw6_enabled = is_cw6_enabled;