perf kvm/riscv: Port perf kvm stat to RISC-V

perf kvm/riscv: Port perf kvm stat to RISC-V

'perf kvm stat report/record' generates a statistical analysis of KVM
events and can be used to analyze guest exit reasons.

"report" reports statistical analysis of guest exit events.

To record kvm events on the host:
 # perf kvm stat record -a

To report kvm VM EXIT events:
 # perf kvm stat report --event=vmexit

Signed-off-by: Shenlin Liang <liangshenlin@eswincomputing.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20240422080833.8745-3-liangshenlin@eswincomputing.com
Signed-off-by: Anup Patel <anup@brainfault.org>