Revert r306095: [mips] Fix reg positions in the aui/daui instructions
ELF/mips-plt-r6.s in lld-test is failing. Reverting the change.
Original commit message:
[mips] Fix register positions in the aui/daui instructions Swapped the position of the rt and rs register in the aut/daui instructions for mips32r6 and mips64r6. With this change, the format of the generated instructions complies with specifications and GCC. Patch by Milos Stojanovic.