arm: vt8500: Convert irq.c for multiplatform integration

This patch converts arch-vt8500/irq.c to MULTI_IRQ_HANDLER and
SPARSE_IRQ. IRQ domain is changed from legacy to linear.

Also, remove legacy code in include/mach/entry-macro.S and
include/mach/irq.h to prepare for multiplatform.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 73067ef..97b40d0 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -951,6 +951,8 @@
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_GPIO
 	select HAVE_CLK
+	select MULTI_IRQ_HANDLER
+	select SPARSE_IRQ
 	select USE_OF
 	help
 	  Support for VIA/WonderMedia VT8500/WM85xx System-on-Chip.