RISC-V: KVM: Introduce KVM_EXIT_FAIL_ENTRY_NO_VSFILE

RISC-V: KVM: Introduce KVM_EXIT_FAIL_ENTRY_NO_VSFILE

Currently, we return CSR_HSTATUS as hardware_entry_failure_reason when
kvm_riscv_aia_alloc_hgei failed in KVM_DEV_RISCV_AIA_MODE_HWACCEL
mode, which is vague so it is better to return a well defined value
KVM_EXIT_FAIL_ENTRY_NO_VSFILE provided via uapi/asm/kvm.h.

Signed-off-by: BillXiang <xiangwencheng@lanxincomputing.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20250923053851.32863-1-xiangwencheng@lanxincomputing.com
Signed-off-by: Anup Patel <anup@brainfault.org>