Currenly the CNTFRQ register and system timer is initialized in BL31 for
use by the normal world. During firmware update, the NS-BL1 or NS-BL2U
may need to access the system timer. Hence this patch duplicates the
CNTFRQ and system timer initialization in BL1 as well.

Signed-off-by: Soby Mathew <soby.mathew@arm.com>
Change-Id: I1ede78b4ae64080fb418cb93f3e48b26d7b724dc