PCI: xilinx-nwl: Make explicitly non-modular

PCI: xilinx-nwl: Make explicitly non-modular

This code is not being built as a module by anyone:

  drivers/pci/host/Kconfig:config PCIE_XILINX_NWL
  drivers/pci/host/Kconfig:  bool "NWL PCIe Core"

Remove uses of MODULE_DESCRIPTION(), MODULE_AUTHOR(), MODULE_LICENSE(),
etc., so that when reading the driver there is no doubt it is builtin-only.
The information is preserved in comments at the top of the file.

Explicitly disallow driver unbind, since that doesn't have a sensible use
case anyway, and it allows us to drop the ".remove" code for non-modular
drivers.  Delete several functions only used by the remove function.

Note that for non-modular code, builtin_platform_driver() uses the same
init level priority as module_platform_driver(), so this doesn't change
init ordering.

[bhelgaas: changelog]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Michal Simek <michal.simek@xilinx.com>
CC: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
CC: Marc Zyngier <marc.zyngier@arm.com>
CC: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>