PCI: Simplify pcie_bus_configure_settings() interface

PCI: Simplify pcie_bus_configure_settings() interface

Based on a patch by Jon Mason (see URL below).

All users of pcie_bus_configure_settings() pass arguments of the form
"bus, bus->self->pcie_mpss".  The "mpss" argument is redundant since we
can easily look it up internally.  In addition, all callers check
"bus->self" for NULL, which we can also do internally.

This patch simplifies the interface and the callers.  No functional change.

Bug 1496843

Change-Id: I6f4b3c0e2bc359fb260e0f8e253dd737d9be4e25
Reference: http://lkml.kernel.org/r/1317048850-30728-2-git-send-email-mason@myri.com
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Reviewed-on: http://git-master/r/449151
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>