The commit c144f63833 removed INSN_CLASS_A and
added INSN_CLASS_ZAAMO and INSN_CLASS_ZALRSC instead,
which broke the build of the sim for riscv targets.
Fix that by using the new INSN_CLASS types.
Fixes: c144f63833 ("RISC-V: Support B, Zaamo and Zalrsc extensions.")
Approved-By: Tom Tromey <tom@tromey.com>