powerpc: Fix a few opcodes to support x2/x4 usage

4 jobs for powerpc in 1 minute and 10 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #635666
debian sid

00:00:51

passed #635669
docker windows 1607
msys2

00:01:08

passed #635667
docker windows 1607
vs2017 amd64

00:01:10

passed #635668
docker windows 1607
vs2017 x86

00:01:09