powerpc/44x/Akebono: Remove select of IBM_EMAC_RGMII_WOL

Commit 2a2c74b2 ("IBM Akebono: Add the Akebono platform") added a
select of IBM_EMAC_RGMII_WOL. But that Kconfig symbol isn't (yet) part
of the tree. So this select has been a nop since that commit was
included in v3.16-rc1.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>