[AArch64] Simplify AES*Tied pseudo expansion (NFC).
[AArch64] Simplify AES*Tied pseudo expansion (NFC).

Summary:
Suggested by @t.p.northover in https://bugs.llvm.org/show_bug.cgi?id=34015.


Reviewers: javed.absar, t.p.northover, rengolin

Reviewed By: t.p.northover

Subscribers: aemerson, kristof.beyls, llvm-commits, t.p.northover

Differential Revision: https://reviews.llvm.org/D36223

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@309821 91177308-0d34-0410-b5e6-96231b3b80d8

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