PCI: rpaphp: Add MODULE_DESCRIPTION

This patch adds a brief MODULE_DESCRIPTION to rpadlpar_io kernel modules
(descriptions taken from Kconfig file).

Signed-off-by: Mamatha Inamdar <mamatha4@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200924051343.16052.9571.stgit@localhost.localdomain