ram: rk3399: Compute stride for 1 channel a

Add stride computation for the sdram which support
single channel a

This configuration available in NanoPi NEO4 and the
same can work with existing rk3399-sdram-ddr3-1866.dtsi

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: YouMin Chen <cym@rock-chips.com>
Reviewed-by: Kever Yang <Kever.yang@rock-chips.com>
diff --git a/drivers/ram/rockchip/sdram_rk3399.c b/drivers/ram/rockchip/sdram_rk3399.c
index c626ef6..8bbacb5 100644
--- a/drivers/ram/rockchip/sdram_rk3399.c
+++ b/drivers/ram/rockchip/sdram_rk3399.c
@@ -1211,6 +1211,10 @@
 		chinfo |= 1 << channel;
 	}
 
+	/* stride calculation for 1 channel */
+	if (params->base.num_channels == 1 && chinfo & 1)
+		return 0x17;	/* channel a */
+
 	/* stride calculation for 2 channels, default gstride type is 256B */
 	if (ch_cap[0] == ch_cap[1]) {
 		cap = ch_cap[0] + ch_cap[1];