KVM: Use vfree for memory allocated by vcalloc()/__vcalloc()

commit 37b2a651

("KVM: use __vcalloc for very large allocations")
replaced kvzalloc()/kvcalloc() with vcalloc(), but didn't replace kvfree()
with vfree().

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Link: https://lore.kernel.org/r/20240131012357.53563-1-lirongqing@baidu.com
Signed-off-by: Sean Christopherson <seanjc@google.com>