Add 64-bit divide library routines for Cortex-M, Cortex-M0

These are needed for fixed-point math calculations.

Taken from the same public repo where we got the 32-bit divide
routines for Cortex-M0.  With minor modifications to match changes
we've made so far for the existing divide routines (put each function
in its own section, delete dead code, etc.)

BUG=chrome-os-partner:36126
BRANCH=minnie
TEST=hack in a debug console command to allow arbitrary int64 divide, see that
     it works as expected

Change-Id: I987dbca7c806c71bc38fa816971ac3a54c1641a5
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/244501
Reviewed-by: Alec Berg <alecaberg@chromium.org>
6 files changed