riscv: kvm: fix vector context allocation leak

riscv: kvm: fix vector context allocation leak

When the second kzalloc (host_context.vector.datap) fails in
kvm_riscv_vcpu_alloc_vector_context, the first allocation
(guest_context.vector.datap) is leaked. Free it before returning.

Fixes: 0f4b82579716 ("riscv: KVM: Add vector lazy save/restore support")
Cc: stable@vger.kernel.org
Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>
Reviewed-by: Andy Chiu <andybnac@gmail.com>
Link: https://lore.kernel.org/r/20260316151612.13305-1-osama.abdelkader@gmail.com
Signed-off-by: Anup Patel <anup@brainfault.org>