OMAP1: Amstrad Delta: add a handler for processing interruptsgenerated by the FIQ routine

This patch introduces an IRQ handler used for processing interrupts generated
by the FIQ handler when it decides there are data ready for processing.

The handler further invokes device specific interrupt routines based on
interrupt source counters passed from the FIQ handler.

The handler setup function is intended to be called from the board
provided init_machine() callback.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
[tony@atomide.com: Updated to include linux/io.h instead of plat/io.h
Signed-off-by: Tony Lindgren <tony@atomide.com>