xen/gnttab: leave lazy MMU mode in the case of a m2p override failure
xen/gnttab: leave lazy MMU mode in the case of a m2p override failure

Commit f62805f1 introduced a bug where lazy MMU mode isn't exited if a
m2p_add/remove_override call fails.

Acked-by: Stefano Stabellini <22a0c6385d750d07aa383c9f813cf6f0228657d8@eu.citrix.com>
Cc: Boris Ostrovsky <b41c17b861974b03cec38e3ec2992769b9bfae55@oracle.com>
Reviewed-by: David Vrabel <b9d45bd1f671e508cd8daa63dfc3cabb597562df@citrix.com>
Reviewed-by: Anthony Liguori <0212dd00c21e75e861d960b0cf505645317aaa0b@amazon.com>
Cc: 196a79ea1bad81d8c954adf793448b0a45442f28@lists.xenproject.org
Cc: 2578944098299abf708b08eff6fcf60565553586@vger.kernel.org
Signed-off-by: Matt Wilson <260f5074942ca36dab941199ff6b19fcaa26ccde@amazon.com>
Signed-off-by: Konrad Rzeszutek Wilk <da3a51b335cef0eb0e2c329c5ef6bcd6acef687a@oracle.com>
CC: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs