powerpc/85xx: TQM8548: use proper phy-handles for enet2 and enet3

For enet2 and enet3 the wrong phy-handles have been used in DTS files
of the TQM8548 modules.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>