Revert va_list padding

This reverts commits 4bf35d58f0b7ddc5bb6e741e0e0965fe05efc81c and
b792e39c8a0f834027e8b5079793ee2c8c84eacb.  The va_list type is left
as it was originally for both i386 and ARM.

(cherry picked from commit cb544bb5bb96a0e0b3d44e89d927d150406e233d)

Conflicts:
	gcc/config/arm/arm.c