ARM: EXYNOS: fix non-SMP builds for EXYNOS4

This patch fixes the following build issue, which happens only if
SMP has been disabled:

arch/arm/mach-exynos/built-in.o: In function `exynos4_pm_resume':
arch/arm/mach-exynos/pm.c:387: undefined reference to `scu_enable'
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-exynos/pm.c

@@ -384,7 +384,9 @@ static void exynos4_pm_resume(void)
 
 	exynos4_restore_pll();
 
+#ifdef CONFIG_SMP
 	scu_enable(S5P_VA_SCU);
+#endif
 
 #ifdef CONFIG_CACHE_L2X0
 	s3c_pm_do_restore_core(exynos4_l2cc_save, ARRAY_SIZE(exynos4_l2cc_save));