drm: Add acquire ctx to ->gamma_set hook

Atomic helpers really want this instead of the hacked-up legacy
backoff trick, which unfortunately prevents drivers from using their
own private drm_modeset_locks.

Aside: There's a few atomic drivers (nv50, vc4, soon vmwgfx) which
don't yet use the new atomic color mgmt/gamma table stuff. Would be
nice if they could switch over and just hook up
drm_atomic_helper_legacy_gamma_set() instead.

Cc: Dave Airlie <airlied@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Sinclair Yeh <syeh@vmware.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Eric Anholt <eric@anholt.net>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170403083304.9083-13-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 6078654..ef9f3a2 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -2026,7 +2026,8 @@ static int vmw_du_update_layout(struct vmw_private *dev_priv, unsigned num,
 
 int vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
 			  u16 *r, u16 *g, u16 *b,
-			  uint32_t size)
+			  uint32_t size,
+			  struct drm_modeset_acquire_ctx *ctx)
 {
 	struct vmw_private *dev_priv = vmw_priv(crtc->dev);
 	int i;