s390: hotplug: make pci_hpc explicitly non-modular

The Kconfig currently controlling compilation of this code is:

drivers/pci/hotplug/Kconfig:config HOTPLUG_PCI_S390
drivers/pci/hotplug/Kconfig:    bool "System z PCI Hotplug Support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the couple traces of modular infrastructure use, so that
when reading the driver there is no doubt it is builtin-only.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

We don't exchange module.h for init.h or export.h since the file
does not contain any initcalls or EXPORT of symbols.

Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-s390@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>