drm/amd/amdgpu: fix Tonga S3 resume hang on rhel6.8

1. security firmware loading has moved to sw init, so this code
   is useless.
2. it seems that driver could not call request_firmware on
   kernel 2.6, when S3 resume. for request firmware depends on
   userspace, at this time, userspace is freeze.
Signed-off-by: NJim Qu <Jim.Qu@amd.com>
Acked-by: NHuang Rui <ray.huang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

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

@@ -840,9 +840,6 @@ static int amdgpu_cgs_get_firmware_info(struct cgs_device *cgs_device,
 		const struct common_firmware_header *header;
 		struct amdgpu_firmware_info *ucode = NULL;
 
-		if (CGS_UCODE_ID_SMU_SK == type)
-			amdgpu_cgs_rel_firmware(cgs_device, CGS_UCODE_ID_SMU);
-
 		if (!adev->pm.fw) {
 			switch (adev->asic_type) {
 			case CHIP_TOPAZ: