ARM: OMAP: Fix OMAP2 clock.c typo

A forgotten parenthesis in clock.c caused the PLL stabilization loop
to not be executed correctly.
Signed-off-by: Samuel Ortiz <samuel.ortiz@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>

arch/arm/mach-omap2/clock.c

@@ -103,7 +103,7 @@ static void omap2_clk_fixed_enable(struct clk *clk)
 	else if (clk == &apll54_ck)
 		cval = (1 << 6);
 
-	while (!CM_IDLEST_CKGEN & cval) {		/* Wait for lock */
+	while (!(CM_IDLEST_CKGEN & cval)) {		/* Wait for lock */
 		++i;
 		udelay(1);
 		if (i == 100000)