MIPS release changed encodes of some instructions, include ll/sc etc.
if .set mips4 on mips r6, as will generate some wrong encode of some instructions.
The patch for o32.S is taken from OpenWrt packages repo 3a7a4bf "libffi:
fix MIPS softfloat build issue with current binutils"
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>