Accept the gas mnemonics "ud2a" and "ud2b"; fix ud0
Accept the gas mnemonics "ud2a" and "ud2b"; fix ud0

Accept the gas mnemonics "ud2a" and "ud2b" for the instructions we
call ud2 and ud1 respectively, and Intel call ud2 and undocumented :)

Also, 0F FF is ud0 regardless of prefixes, at least as far as we know.

projedi/nasm,Distrotech/nasm,techkey/nasm,techkey/nasm,Distrotech/nasm,projedi/nasm,projedi/nasm,letolabs/nasm,letolabs/nasm,techkey/nasm,projedi/nasm,letolabs/nasm,techkey/nasm,techkey/nasm,turingstudio/nasm,turingstudio/nasm,turingstudio/nasm,projedi/nasm,Distrotech/nasm,turingstudio/nasm,Distrotech/nasm