aeroflex/greth: fix warning about unused variable

Fix following warning:
aeroflex/greth.c:1326:11: warning: unused variable 'phy' [-Wunused-variable]

The variable was unused - remove it.
It looks like this warning has been there forever - was found by an
allyesconfig build of sparc32.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Kristoffer Glembo <kristoffer@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>