[NFC] [AArch64] Refactor predicate register class decode functions (#97412)
In a previous PR #81716, a new decoder function was added to
llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp. During
code review it was suggested that, as most of the decoder functions were
very similar in structure, that they be refactored into a single,
templated function. I have added the refactored function, removed the
definitions of the replaced functions, and replaced the references to
the replaced functions in AArch64Disassembler.cpp and
llvm/lib/Target/AArch64/AArch64RegisterInfo.td. To reduce the number of
duplicate references in AArch64RegisterInfo.td, I have also made a small
change to llvm/utils/TableGen/DecoderEmitter.cpp.
llvm-project
a46d60ad - [NFC] [AArch64] Refactor predicate register class decode functions (#97412)
