ARM: exynos: Cleanup cppcheck shifting warning

Fix warning from cppcheck tool:
"Shifting signed 32-bit value by 31 bits is undefined behaviour errors"
Signed-off-by: NPhong Tran <tranmanphong@gmail.com>
Signed-off-by: NKrzysztof Kozlowski <krzk@kernel.org>

arch/arm/mach-exynos/suspend.c

@@ -285,7 +285,7 @@ static void exynos_pm_set_wakeup_mask(void)
 	 * Set wake-up mask registers
 	 * EXYNOS_EINT_WAKEUP_MASK is set by pinctrl driver in late suspend.
 	 */
-	pmu_raw_writel(exynos_irqwake_intmask & ~(1 << 31), S5P_WAKEUP_MASK);
+	pmu_raw_writel(exynos_irqwake_intmask & ~BIT(31), S5P_WAKEUP_MASK);
 }
 
 static void exynos_pm_enter_sleep_mode(void)