Preparatory work to introduce a second SoC : 5/5
All Cortex-M3/4 have the same NVIC registers at the same address.
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
BUG=None
TEST=run EC firmware on BDS and check a few console commands
Change-Id: I6b03c4c1fb21850be8c8afb711ea44134c8cdea1