fm10k: Unlock mailbox on VLAN addition failures
fm10k: Unlock mailbox on VLAN addition failures

After grabbing the mailbox lock and detecting an error, the lock must be
released before the error code can be returned.

Signed-off-by: Matthew Vick <d265f499ad1500ed47610cc699ddce50365eb4ad@intel.com>
Tested-by: Aaron Brown <4723df1d9a4136f7b76e1bf6434e33afc91d2139@intel.com>
Signed-off-by: Jeff Kirsher <87e35f5be20bb3e67f4ba6b86f5f6be3085b1b3a@intel.com>

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