utils: move BIT(n) macro to utils.h

We are duplicating this macro define, and it is useful enough
to be placed in the common place.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/plat/rockchip/common/include/plat_private.h b/plat/rockchip/common/include/plat_private.h
index a093e79..b2234a6 100644
--- a/plat/rockchip/common/include/plat_private.h
+++ b/plat/rockchip/common/include/plat_private.h
@@ -75,10 +75,6 @@
  ******************************************************************************/
 #define REG_MSK_SHIFT	16
 
-#ifndef BIT
-#define BIT(nr)			(1 << (nr))
-#endif
-
 #ifndef WMSK_BIT
 #define WMSK_BIT(nr)		BIT((nr) + REG_MSK_SHIFT)
 #endif
diff --git a/plat/rockchip/rk3399/drivers/soc/soc.h b/plat/rockchip/rk3399/drivers/soc/soc.h
index 742bb7b..28590f2 100644
--- a/plat/rockchip/rk3399/drivers/soc/soc.h
+++ b/plat/rockchip/rk3399/drivers/soc/soc.h
@@ -31,6 +31,8 @@
 #ifndef __SOC_H__
 #define __SOC_H__
 
+#include <utils.h>
+
 #define GLB_SRST_FST_CFG_VAL	0xfdb9
 #define GLB_SRST_SND_CFG_VAL	0xeca8