staging: et131x: Remove typedefs from et1310_phy.h

Fixes the associated checkpatch warnings.
Tested with ifconfig/general use of a device (Agere Systems ET-131x PCI-E
Ethernet Controller (rev 02)).

Signed-off-by: Mark Einon <mark.einon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>