mips: change insn shift when x2/x4 is present
mips: change insn shift when x2/x4 is present

jpakkane/orc,okuoku/nmosh-orc,okuoku/nmosh-orc,ijsf/OpenWebRTC-orc,Distrotech/orc,mojaves/orc,jpakkane/orc,Distrotech/orc,jpakkane/orc,mojaves/orc,MOXfiles/orc,okuoku/nmosh-orc,Distrotech/orc,ijsf/OpenWebRTC-orc,MOXfiles/orc,ijsf/OpenWebRTC-orc,mojaves/orc,MOXfiles/orc