ARM: EXYNOS: Select SPARSE_IRQ for Exynos

This patch adds selection of CONFIG_SPARSE_IRQ for ARCH_EXYNOS, since it
is required by multiplatform and allows to remove the legacy mach/irqs.h
header.

To make this possible, a dummy IRQ_EINT_BIT macro is added to pm-core.h
header to allow plat-samsung/pm.c compile. This macro is irrelevant for
Exynos and will be removed after reworking Samsung pm code for
multiplatform compatibility.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 17a2d6a..14f6e11 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -807,6 +807,7 @@
 	select HAVE_S3C2410_WATCHDOG if WATCHDOG
 	select HAVE_S3C_RTC if RTC_CLASS
 	select NEED_MACH_MEMORY_H
+	select SPARSE_IRQ
 	select USE_OF
 	help
 	  Support for SAMSUNG's EXYNOS SoCs (EXYNOS4/5)