[RISCV] Don't emit save-restore call if function is a interrupt handler

It has to save all caller-saved registers before a call in the handler.
So don't emit a call that save/restore registers.

Reviewed By: simoncook, luismarques, asb

Differential Revision: https://reviews.llvm.org/D100532

GitOrigin-RevId: 2893570e86dbb6b9b6b7f7779d9988ff6a686fe1
2 files changed