riscv: Fix RISCV builds by updating its use of pseudoInst().

riscv: Fix RISCV builds by updating its use of pseudoInst().

The signature of the function and RISCV's use of it changed
simultaneously, were independently verified, and then separately merged.
The combination of the two does not build successfully.

This change updates RISCV so it uses the new signature.

Change-Id: I6a944e664640c9086583d546870ed1fbfa84a3e7
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/27163
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Nils Asmussen <nils.asmussen@barkhauseninstitut.org>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: Gem5 Cloud Project GCB service account <345032938727@cloudbuild.gserviceaccount.com>
Tested-by: kokoro <noreply+kokoro@google.com>