OMAP4430: TWL data: update retention voltages to spec rev 0.6

Update retention voltages from Operating Conditions Data Manual
Addendum Revision 0.6 (August 2011).

Note: vdd_iva is used as TWL's vcore2 is common between OMAP4430
and OMAP4460 - hence the update is done for 4460 as well(follow
on patch updates rest of the domain voltages to the same voltage
for OMAP4460).

Change-Id: I68a561049f3faf54b877a4d6293682829ee99b62
Signed-off-by: Nishanth Menon <nm@ti.com>

Conflicts:
	arch/arm/mach-omap2/omap_twl.c

Conflicts:
	arch/arm/mach-omap2/omap_twl.c