arm/reset: relocate the vector table when a non-XIP image

The processor is made aware that the vector table built in the image is
located at the start of SRAM in the case of a non-XIP image, rather than
at 0 in as is the case in XIP images.

Change-Id: I40b28ca32daf3e8930f103224766ed4e0ccc88e0
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>