drm/sun4i: Set the coef_rdy bit right after the coef have been set

The COEF_RDY bit is used to tell the hardware that new FIR filters
coefficients have been written to the registers and that the hardware
should take them into account starting next frame.
Reviewed-by: NPaul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: NMaxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190118145133.21281-20-paul.kocialkowski@bootlin.com

drivers/gpu/drm/sun4i/sun4i_frontend.c

@@ -96,6 +96,10 @@ static void sun4i_frontend_scaler_init(struct sun4i_frontend *frontend)
 			     sun4i_frontend_vert_coef[i]);
 	}
 
+	regmap_write_bits(frontend->regs,
+			  SUN4I_FRONTEND_FRM_CTRL_REG,
+			  SUN4I_FRONTEND_FRM_CTRL_COEF_RDY,
+			  SUN4I_FRONTEND_FRM_CTRL_COEF_RDY);
 }
 
 int sun4i_frontend_init(struct sun4i_frontend *frontend)