PHYLIB: Spinlock fixes for softirqs

Use spin_lock_bh()/spin_unlock_bh() for the phydev lock throughout as it
is used in phy_timer() that is called as a softirq and all the other
operations may happen in the user context.

There has been a change recently that did such a conversion for some of the
operations on the lock, but some have been left intact.  Many of them,
perhaps all, may be called in the user context and I was able to trigger
recursive spinlock acquisition indeed, so I think for the sake of long-term
maintenance it is best to convert them all, even if unnecessarily for one
or two -- better safe than sorry.

Perhaps one in phy_timer() could actually be skipped as only called as a
softirq -- I can send an update if that sounds like a good idea.

Checked with checkpatch.pl and at the runtime.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>