3c59x: Fix deadlock in vortex_error()

3c59x: Fix deadlock in vortex_error()

This fixes a bug introduced in commit
de847272149365363a6043a963a6f42fb91566e2
"3c59x: Use fine-grained locks for MII and windowed register access".

vortex_interrupt() holds vp->window_lock over multiple register
accesses to reduce locking overhead.  However it also needs to call
vortex_error() sometimes, and that uses the regular functions for
access to windowed registers, which will try to acquire window_lock
again.

Therefore, drop window_lock around the call to vortex_error() and set
the window afterward reacquiring the lock.  Since vortex_error() may
call vortex_rx(), which *does* require its caller to hold window_lock,
lift that call up into vortex_interrupt().  This also removes the
potential for calling vortex_rx() on a later-generation NIC.

Reported-and-tested-by: Jens Schüßler <jgs@trash.net> [in Debian's 2.6.32]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>