drm/amdgpu: Use drm_dbg_kms for reporting failure to get a GEM FB

drm_err meant broken user space could spam dmesg.

Fixes: f258907f "drm/amdgpu: Verify bo size can fit framebuffer size on init."
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <mdaenzer@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1057,7 +1057,7 @@ int amdgpu_display_gem_fb_init(struct drm_device *dev,
 
 	return 0;
 err:
-	drm_err(dev, "Failed to init gem fb: %d\n", ret);
+	drm_dbg_kms(dev, "Failed to init gem fb: %d\n", ret);
 	rfb->base.obj[0] = NULL;
 	return ret;
 }
@@ -1091,7 +1091,7 @@ int amdgpu_display_gem_fb_verify_and_init(
 
 	return 0;
 err:
-	drm_err(dev, "Failed to verify and init gem fb: %d\n", ret);
+	drm_dbg_kms(dev, "Failed to verify and init gem fb: %d\n", ret);
 	rfb->base.obj[0] = NULL;
 	return ret;
 }