qed: Unlock on error in qed_vf_pf_acquire()

qed: Unlock on error in qed_vf_pf_acquire()

Orabug: 26783820

My static checker complains that we're holding a mutex on this error
path.  Let's goto exit instead of returning directly.

Fixes: b0bccb69eba3 ("qed: Change locking scheme for VF channel")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ Upstream commit 66117a9d9a8ca948680d6554769ef9e88f936954 ]
Signed-off-by: Somasundaram Krishnasamy <somasundaram.krishnasamy@oracle.com>