kvm: Fix kvm_get_page_retry_io __gup retval check

Confusion around -EBUSY and zero (inside a BUG_ON no less).

Reported-by: Andrea Arcangeli <[email protected]>
Signed-off-by: Andres Lagar-Cavilla <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
1 file changed