irqchip: or1k-pic: Migrate from arch/openrisc/

In addition to consolidating the or1k-pic with other interrupt
controllers, this makes OpenRISC less tied to its on-cpu
interrupt controller.

All or1k-pic specific parts are moved out of irq.c and into
drivers/irqchip/irq-or1k-pic.c

In that transition, the functionality have been divided into
three chip variants.
One that handles level triggered interrupts, one that handles edge
triggered interrupts and one that handles the interrupt
controller that is present in the or1200 OpenRISC cpu
implementation.

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Link: https://lkml.kernel.org/r/1401136302-27654-1-git-send-email-stefan.kristiansson@saunalahti.fi
Acked-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

arch/openrisc/Kconfig

@@ -22,6 +22,7 @@ config OPENRISC
 	select GENERIC_STRNLEN_USER
 	select MODULES_USE_ELF_RELA
 	select HAVE_DEBUG_STACKOVERFLOW
+	select OR1K_PIC
 
 config MMU
 	def_bool y