rtc: Add twl6030 RTC support

This patch adds support for RTC in phoenix TWL6030.
Register offset addresses have changed in TWL6030
rtc-twl.c will hence forth support all twl RTC (4030, 5030, 6030 ..)

Signed-off-by: Balaji T K <balajitk@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>