Fixing cpu_class_is_omap2() parentheses warning

Fixing the follow warning
arch/arm/plat-omap/usb.c: In function 'omap_usb0_init':
arch/arm/plat-omap/usb.c:136: warning: suggest parentheses around && within ||
Signed-off-by: Ragner Magalhaes <ragner.magalhaes@indt.org.br>
Signed-off-by: Tony Lindgren <tony@atomide.com>

include/asm-arm/arch-omap/cpu.h

@@ -273,6 +273,6 @@ IS_OMAP_TYPE(3430, 0x3430)
 /* Macros to detect if we have OMAP1 or OMAP2 */
 #define cpu_class_is_omap1()	(cpu_is_omap730() || cpu_is_omap15xx() || \
 				cpu_is_omap16xx())
-#define cpu_class_is_omap2()	cpu_is_omap24xx() || cpu_is_omap34xx()
+#define cpu_class_is_omap2()	(cpu_is_omap24xx() || cpu_is_omap34xx())
 
 #endif