e1000e: fix double release of mutex

e1000e: fix double release of mutex

commit 30bb0e0dce78427f3e5cb728d6b5ea73acbefffa upstream.

During a reset, releasing the swflag after it failed to be acquired would
cause a double unlock of the mutex.  Instead, test whether acquisition of
the swflag was successful and if not, do not release the swflag.  The reset
must still be done to bring the device to a quiescent state.

This resolves [BUG 12200] BUG: bad unlock balance detected! e1000e
http://bugzilla.kernel.org/show_bug.cgi?id=12200

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>