PCI: acpiphp: Add missing MODULE_DESCRIPTION() macro

With ARCH=arm64, make allmodconfig && make W=1 C=1 reports:

  WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/pci/hotplug/acpiphp_ampere_altra.o

Add the missing MODULE_DESCRIPTION().

Link: https://lore.kernel.org/r/20240612-md-drivers-pci-hotplug-v1-1-2b30d14d783d@quicinc.com


Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>