ram: rk3328: Use correct frequency units in function

Fix a pair of tests in phy_dll_bypass_set() that used incorrect units
for the DDR frequency, causing the DRAM controller to be misconfigured
in most cases.

Signed-off-by: Simon South <simon@simonsouth.net>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/ram/rockchip/sdram_rk3328.c b/drivers/ram/rockchip/sdram_rk3328.c
index 656696a..0541bba 100644
--- a/drivers/ram/rockchip/sdram_rk3328.c
+++ b/drivers/ram/rockchip/sdram_rk3328.c
@@ -311,12 +311,12 @@
 	setbits_le32(PHY_REG(phy_base, 0x56), 1 << 4);
 	clrbits_le32(PHY_REG(phy_base, 0x57), 1 << 3);
 
-	if (freq <= (400 * MHz))
+	if (freq <= 400)
 		/* DLL bypass */
 		setbits_le32(PHY_REG(phy_base, 0xa4), 0x1f);
 	else
 		clrbits_le32(PHY_REG(phy_base, 0xa4), 0x1f);
-	if (freq <= (680 * MHz))
+	if (freq <= 680)
 		tmp = 2;
 	else
 		tmp = 1;