drm/amdgpu/psp: switch to use sos_offset_bytes member as sys_bin_size

Navi10 will have toc built-in sos binary so that using header.ucode_size_bytes
minus sos_size_bytes actually is not sys_bin_size.

Using sos_offset_bytes works for both vega20 (psp_firmware_header_v1_0) and
navi10 (psp_firmware_header_v1_1)
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/psp_v11_0.c

@@ -90,8 +90,7 @@ static int psp_v11_0_init_microcode(struct psp_context *psp)
 		adev->psp.sos_fw_version = le32_to_cpu(sos_hdr->header.ucode_version);
 		adev->psp.sos_feature_version = le32_to_cpu(sos_hdr->ucode_feature_version);
 		adev->psp.sos_bin_size = le32_to_cpu(sos_hdr->sos_size_bytes);
-		adev->psp.sys_bin_size = le32_to_cpu(sos_hdr->header.ucode_size_bytes) -
-				le32_to_cpu(sos_hdr->sos_size_bytes);
+		adev->psp.sys_bin_size = le32_to_cpu(sos_hdr->sos_offset_bytes);
 		adev->psp.sys_start_addr = (uint8_t *)sos_hdr +
 				le32_to_cpu(sos_hdr->header.ucode_array_offset_bytes);
 		adev->psp.sos_start_addr = (uint8_t *)adev->psp.sys_start_addr +