irqchip: Add TB10x interrupt controller driver

The SOC interrupt controller driver for the Abilis Systems TB10x series of
SOCs based on ARC700 CPUs.

Signed-off-by: Christian Ruppert <christian.ruppert@abilis.com>
Signed-off-by: Pierrick Hascoet <pierrick.hascoet@abilis.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Cc: devicetree-discuss@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1372177797-9458-1-git-send-email-christian.ruppert@abilis.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>