omap4: control: Add the CONTROL_SMART2IO_PADCONF_2 register definition

This patch adds missing CONTROL_SMART2IO_PADCONF_2 register
definition

Change-Id: I9bec7e1e95e7b86ae6c5c4e0f457370c8db20e4a
Signed-off-by: Ruslan Bilovol <x0155540@ti.com>