PNP: Remove prehistoric deadcode

PNP: Remove prehistoric deadcode

pnp_remove_card() is currently unused, it has been since it was
added in 2003's BKrev: 3e6d3f19XSmESWEZnNEReEJOJW5SOw

pnp_unregister_protocol() is currently unused,  it has been since
it was added in 2002's BKrev: 3df0cf6d4FVUKndhbfxjL7pksw5PGA

Remove them, and pnp_remove_card_device() and __pnp_remove_device()
which are now no longer used.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://patch.msgid.link/20250307214936.74504-1-linux@treblig.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>