scc_pata: fix module unloading

scc_pata host driver predated module unloading support for IDE host
drivers so even though it supports PCI hot-unplug and implements
PCI device ->remove method it doesn't allow module removal.  Fix it.

Add missing __init/__exit tags to module_init/module_exit functions
while at it (from Peter Huewe).

Noticed-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>