video: ipu: simplify if else code

Simplify if/else code, since if channel equals to MEM_BG_SYNC or
MEM_FG_SYNC, we have value 5 for 'dc_chan'.
Signed-off-by: NPeng Fan <Peng.Fan@freescale.com>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Reviewed-by: NStefano Babic <sbabic@denx.de>

drivers/video/ipu_disp.c

@@ -611,11 +611,9 @@ void ipu_dp_dc_enable(ipu_channel_t channel)
 	uint32_t reg;
 	uint32_t dc_chan;
 
-	if (channel == MEM_FG_SYNC)
-		dc_chan = 5;
 	if (channel == MEM_DC_SYNC)
 		dc_chan = 1;
-	else if (channel == MEM_BG_SYNC)
+	else if ((channel == MEM_BG_SYNC) || (channel == MEM_FG_SYNC))
 		dc_chan = 5;
 	else
 		return;