clk: imx: Use imx_mmdc_mask_handshake() API for masking MMDC channel

Use imx_mmdc_mask_handshake() API instead of programming CCM
register directly in each platform to mask unused MMDC channel's
handshake.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

drivers/clk/imx/clk-imx6sl.c

@@ -17,8 +17,6 @@
 
 #include "clk.h"
 
-#define CCDR				0x4
-#define BM_CCM_CCDR_MMDC_CH0_MASK	(1 << 17)
 #define CCSR			0xc
 #define BM_CCSR_PLL1_SW_CLK_SEL	(1 << 2)
 #define CACRR			0x10
@@ -414,8 +412,7 @@ static void __init imx6sl_clocks_init(struct device_node *ccm_node)
 	clks[IMX6SL_CLK_USDHC4]       = imx_clk_gate2("usdhc4",       "usdhc4_podf",       base + 0x80, 8);
 
 	/* Ensure the MMDC CH0 handshake is bypassed */
-	writel_relaxed(readl_relaxed(base + CCDR) |
-		BM_CCM_CCDR_MMDC_CH0_MASK, base + CCDR);
+	imx_mmdc_mask_handshake(base, 0);
 
 	imx_check_clocks(clks, ARRAY_SIZE(clks));