phb4: Implement root port initialization
phb4: Implement root port initialization

phb4_root_port_init() was a NOP before, so fix that.

Nothing PHB4-specific here.  Something may be required in future.

Signed-off-by: Russell Currey <b5ebcef270cdc73fa0593440445c07a93ae1bccb@russell.cc>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

stewart-ibm/skiboot,legoater/skiboot,stewart-ibm/skiboot,open-power/skiboot,mikey/skiboot,open-power/skiboot,shenki/skiboot,qemu/skiboot,legoater/skiboot,open-power/skiboot,stewart-ibm/skiboot,mikey/skiboot,open-power/skiboot,legoater/skiboot,qemu/skiboot,qemu/skiboot,legoater/skiboot,qemu/skiboot,shenki/skiboot,shenki/skiboot,legoater/skiboot,qemu/skiboot,shenki/skiboot,open-power/skiboot,mikey/skiboot,shenki/skiboot