cpu/allwinner/a10/clock.h: Add missing bracket

Code checked manually

Change-Id: I92f0b5d47c60c259171c4db90fb5003f4eb8580b
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/20260
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Martin Roth <martinroth@google.com>

src/cpu/allwinner/a10/clock.h

@@ -51,7 +51,7 @@
 #define  APB1_CLK_SRC_32K		(2 << 24)
 #define APB1_RAT_N_MASK			(3 << 16)
 #define  APB1_RAT_N(m)			(((m) & 0x3) << 16)
-#define APB1_RAT_M_MASK			0x1f << 0)
+#define APB1_RAT_M_MASK			(0x1f << 0)
 #define  APB1_RAT_M(n)			(((n) & 0x1f) << 0)
 
 /* PLL5_CFG values */