[PowerPC][NFC] Add a function to determine if a call needs to be NOTOC.

Add the isNoTOCCallInstr function to PPCInstrInfo to determine if a call opcode
does not need a TOC restore after the call. All call opcodes should be listed in
this function. A default unreachable in this function should force future call
opcodes to also be added.

This is a follow up patch to D122012

Reviewed By: jsji, shchenz

Differential Revision: https://reviews.llvm.org/D124415