davinci: da8xx/omapl1: add support for the second sysconfig module

OMAP-L138 adds a second SYSCFG region having useful functionality
like deep sleep, pull up/down control and SATA clock stop.

This patch makes provision for accessing registers from second
SYSCFG region in da8xx code.

Note that OMAP-L137 has a single SYSCFG region.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>