TPS65911: Add new irq definitions

TPS65911 adds new interrupt sources, as well as two new registers
to handle them, one for interrupt status and one for interrupt
masking. The added irqs are:

-VMBCH2 - Low and High threshold
-GPIO1-8 - Rising and falling edge detection
-WTCHDG - Watchdog interrupt
-PWRDN	- PWRDN reset interrupt

The code should handle these new registers only when the chip
version is TPS65911.

Signed-off-by: Jorge Eduardo Candelaria <jedu@slimlogic.co.uk>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>