pch_phub: Fix register miss-setting issue

Register "interrupt delay value" is for GbE which is connected to Bus-m of PCIe.
However currently, the value is set for Bus-n.
As a result, the value is not set correctly.
This patch moves setting the value processing of Bus-n to Bus-m.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>