Revert "Prevent NUll pointer dereference with two PHYs on cpsw"

This reverts commit cfe25560



This can result in a "Unable to handle kernel paging request"
during boot. This was due to using an uninitialised struct member,
data->slaves.

Signed-off-by: Andrew Goodbody <andrew.goodbody@cambrionix.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: David S. Miller <davem@davemloft.net>