OMAP4: Move common twl6030 configuration to twl-common

Reduce the amount of duplicated code by moving the common
configuration for TWL6030 (on OMAP4 platform) to the
twl-common file.
Use the omap4_pmic_get_config function from board files to
properly configure the PMIC with the common fields.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>