ARM: OMAP4: Keyboard: Fix section mismatch in the board file

`keypad_pads' is referred to by `keypad_data' which is
not __initdata, so `keypad_pads' should not be __initdata either.

Signed-off-by: Bjarne Steinsbo <bsteinsbo@gmail.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>