drm/amd/display: Fix incorrect fw_state address in dmub_srv

[WHY]
The fw_state in dmub_srv was assigned with wrong address.
The address was pointed to the firmware region.

[HOW]
Fix the firmware state by using DMUB_DEBUG_FW_STATE_OFFSET
in dmub_cmd.h.

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Lo-an Chen <lo-an.chen@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit f57b38a)

Author: LoAnChen

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

@@ -704,7 +704,7 @@ enum dmub_status dmub_srv_hw_init(struct dmub_srv *dmub,
 	cw6.region.base = DMUB_CW6_BASE;
 	cw6.region.top = cw6.region.base + fw_state_fb->size;
 
-	dmub->fw_state = fw_state_fb->cpu_addr;
+	dmub->fw_state = (void *)((uintptr_t)(fw_state_fb->cpu_addr) + DMUB_DEBUG_FW_STATE_OFFSET);
 
 	region6.offset.quad_part = shared_state_fb->gpu_addr;
 	region6.region.base = DMUB_CW6_BASE;