ARM: Fix push/pop alignment on ARM platforms

This patch adjusts the way we are doing push/pop operations before
making function calls inside of assembly routines.  ARM requires 8
byte aligned stack operations across public interfaces.  This means
that we need to be sure to push multiples of 2 registers.

Fixes #2108

Signed-off-by: Andy Gross <andy.gross@linaro.org>
6 files changed