ARM: orion: use SPARSE_IRQ everywhere

As a preparation for multiplatform support, this moves all the
code using plat-orion over to use sparse irq support, which is
enabled implicitly for multiplatform.

In particular, the hardcoded NR_IRQS macro gets replaced with
a machine specific one that is set in the machine descriptor
in order to set up a static mapping for all legacy interrupts.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
diff --git a/arch/arm/mach-orion5x/net2big-setup.c b/arch/arm/mach-orion5x/net2big-setup.c
index ba73dc7..e91abcc 100644
--- a/arch/arm/mach-orion5x/net2big-setup.c
+++ b/arch/arm/mach-orion5x/net2big-setup.c
@@ -423,6 +423,7 @@
 /* Warning: LaCie use a wrong mach-type (0x20e=526) in their bootloader. */
 MACHINE_START(NET2BIG, "LaCie 2Big Network")
 	.atag_offset	= 0x100,
+	.nr_irqs	= ORION5X_NR_IRQS,
 	.init_machine	= net2big_init,
 	.map_io		= orion5x_map_io,
 	.init_early	= orion5x_init_early,