input: keypad: General fixes to omap-twl4030keypad.c

The following patch fixes some problems in T2 keypad
driver.

Basically we're passing irq number via platform_data,
moving globals to a structure and fixing a problem
while iterating over the keymap.

It might be that we still have a few locking issues
that might be solved on a later version of this same
patch.

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>