am33xx: add SSC enable macro

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
diff --git a/arch/arm/include/asm/arch-am33xx/clock.h b/arch/arm/include/asm/arch-am33xx/clock.h
index 7637457..f00fad3 100644
--- a/arch/arm/include/asm/arch-am33xx/clock.h
+++ b/arch/arm/include/asm/arch-am33xx/clock.h
@@ -42,6 +42,8 @@
 #define MODULE_CLKCTRL_IDLEST_DISABLED		3
 
 /* CM_CLKMODE_DPLL */
+#define CM_CLKMODE_DPLL_SSC_EN_SHIFT		12
+#define CM_CLKMODE_DPLL_SSC_EN_MASK		(1 << 12)
 #define CM_CLKMODE_DPLL_REGM4XEN_SHIFT		11
 #define CM_CLKMODE_DPLL_REGM4XEN_MASK		(1 << 11)
 #define CM_CLKMODE_DPLL_LPMODE_EN_SHIFT		10
diff --git a/board/siemens/rut/board.c b/board/siemens/rut/board.c
index e0ada3f..1752df2 100644
--- a/board/siemens/rut/board.c
+++ b/board/siemens/rut/board.c
@@ -400,7 +400,7 @@
 #if defined(DISPL_PLL_SPREAD_SPECTRUM)
 	writel(0x64, &cmwkup->resv6[3]); /* 0x50 */
 	writel(0x800, &cmwkup->resv6[2]); /* 0x4c */
-	writel(readl(&cmwkup->clkmoddplldisp) | (1 << 12),
+	writel(readl(&cmwkup->clkmoddplldisp) | CM_CLKMODE_DPLL_SSC_EN_MASK,
 	       &cmwkup->clkmoddplldisp); /* 0x98 */
 #endif
 	return 0;