Davinci: tnetv107x: retain psc reg base after init

This is a bugfix for the original tnetv107x submission series.  The psc_regs
base array was being discarded post-init, and this was causing a crash during
post-init clock enable/disable.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>