RISC-V: KVM: Save trap CSRs in kvm_riscv_vcpu_enter_exit()

RISC-V: KVM: Save trap CSRs in kvm_riscv_vcpu_enter_exit()

Save trap CSRs in the kvm_riscv_vcpu_enter_exit() function instead of
the kvm_arch_vcpu_ioctl_run() function so that HTVAL and HTINST CSRs
are accessed in more optimized manner while running under some other
hypervisor.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20241020194734.58686-13-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>