drm/radeon/kms: drop taking lock around crtc lookup.

We only add/remove crtcs at driver load, you cannot remove when
the GPU is running a CS packet since the fd is open, when
GPU hotplugging on radeons actually is needed all this locking
needs a review and I've started re-working kms core locking to deal
with this better. But for now avoid long delays in CS processing when
hotplug detect is happening in a different thread.

this fixes a regression introduced with hotplug detection.

Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/radeon/evergreen_cs.c

···
 	header = radeon_get_ib_value(p, h_idx);
 	crtc_id = radeon_get_ib_value(p, h_idx + 2 + 7 + 1);
 	reg = CP_PACKET0_GET_REG(header);
-	mutex_lock(&p->rdev->ddev->mode_config.mutex);
 	obj = drm_mode_object_find(p->rdev->ddev, crtc_id, DRM_MODE_OBJECT_CRTC);
 	if (!obj) {
 		DRM_ERROR("cannot find crtc %d\n", crtc_id);
···
 		}
 	}
 out:
-	mutex_unlock(&p->rdev->ddev->mode_config.mutex);
 	return r;
 }
 

drivers/gpu/drm/radeon/r100.c

···
 	header = radeon_get_ib_value(p, h_idx);
 	crtc_id = radeon_get_ib_value(p, h_idx + 5);
 	reg = CP_PACKET0_GET_REG(header);
-	mutex_lock(&p->rdev->ddev->mode_config.mutex);
 	obj = drm_mode_object_find(p->rdev->ddev, crtc_id, DRM_MODE_OBJECT_CRTC);
 	if (!obj) {
 		DRM_ERROR("cannot find crtc %d\n", crtc_id);
···
 		ib[h_idx + 3] |= RADEON_ENG_DISPLAY_SELECT_CRTC1;
 	}
 out:
-	mutex_unlock(&p->rdev->ddev->mode_config.mutex);
 	return r;
 }
 

drivers/gpu/drm/radeon/r600_cs.c

···
 	header = radeon_get_ib_value(p, h_idx);
 	crtc_id = radeon_get_ib_value(p, h_idx + 2 + 7 + 1);
 	reg = CP_PACKET0_GET_REG(header);
-	mutex_lock(&p->rdev->ddev->mode_config.mutex);
+
 	obj = drm_mode_object_find(p->rdev->ddev, crtc_id, DRM_MODE_OBJECT_CRTC);
 	if (!obj) {
 		DRM_ERROR("cannot find crtc %d\n", crtc_id);
···
 		ib[h_idx + 4] = AVIVO_D2MODE_VLINE_STATUS >> 2;
 	}
 out:
-	mutex_unlock(&p->rdev->ddev->mode_config.mutex);
 	return r;
 }