syscalls: restore compatibilty with current branch

on arm __NR_stime constant is undefined in asm/unistd.h

add also BIONIC_L define for assembly files (syscalls)
tested on arm and x86 (not on mips)

Change-Id: If5b6a6d3f8b4c10339f8e7b0bf340d02c1cf26cb
Signed-off-by: Tanguy Pruvot <tanguy.pruvot@gmail.com>