powerpc: Update defconfigs which were missing CONFIG_NET.

Commit df568d8e ("scsi: Use 'depends' with LIBFC instead of
'select'.")  removed what happened to be the only instance of 'select
NET'. Defconfigs that were relying on the select now lack networking
support.
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/powerpc/configs/c2k_defconfig

@@ -29,6 +29,7 @@ CONFIG_PM=y
 CONFIG_PCI_MSI=y
 CONFIG_HOTPLUG_PCI=y
 CONFIG_HOTPLUG_PCI_SHPC=m
+CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y
 CONFIG_XFRM_USER=y