clk: rk3399: Fix eMMC get_clk reg offset

Actual eMMC get_clk register is clksel_con22 instead of
clksel_con21.

Fix it.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

drivers/clk/rockchip/clk_rk3399.c

@@ -728,7 +728,7 @@ static ulong rk3399_mmc_get_clk(struct rockchip_cru *cru, uint clk_id)
 		div = 2;
 		break;
 	case SCLK_EMMC:
-		con = readl(&cru->clksel_con[21]);
+		con = readl(&cru->clksel_con[22]);
 		div = 1;
 		break;
 	default: