Clean SecEntryPoint.S for SPL Bootup

Remove redundant initializations.

Signed-off-by: Varad Gautam <varadgautam@gmail.com>
Change SEC To Boot From SPL

Signed-off-by: Varad Gautam <varadgautam@gmail.com>
Write To UART From SEC

Signed-off-by: Varad Gautam <varadgautam@gmail.com>