docs: move get_abi.py to tools/docs

Move this tool out of scripts/ to join the other documentation tools; fix
up a couple of erroneous references in the process.

It's worth noting that this script will fail badly unless one has a
PYTHONPATH referencing scripts/lib/abi.

Reviewed-by: Mauro Carvalho Chehab <[e-mail]>
Acked-by: Jani Nikula <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>

Documentation/Kconfig

···
 	  described at Documentation/ABI/README. Yet, as they're manually
 	  written, it would be possible that some of those files would
 	  have errors that would break them for being parsed by
-	  scripts/get_abi.pl. Add a check to verify them.
+	  tools/docs/get_abi.py. Add a check to verify them.
 
 	  If unsure, select 'N'.
 

Documentation/Makefile

···
 
 # Check for broken ABI files
 ifeq ($(CONFIG_WARN_ABI_ERRORS),y)
-$(shell $(srctree)/scripts/get_abi.py --dir $(srctree)/Documentation/ABI validate)
+$(shell $(srctree)/tools/docs/get_abi.py --dir $(srctree)/Documentation/ABI validate)
 endif
 endif
 

Documentation/sphinx/kernel_abi.py

···
     :license:    GPL Version 2, June 1991 see Linux/COPYING for details.
 
     The ``kernel-abi`` (:py:class:`KernelCmd`) directive calls the
-    scripts/get_abi.py script to parse the Kernel ABI files.
+    AbiParser class to parse the Kernel ABI files.
 
     Overview of directive's argument and options.
 

MAINTAINERS

···
 P:	Documentation/doc-guide/maintainer-profile.rst
 T:	git git://git.lwn.net/linux.git docs-next
 F:	Documentation/
-F:	scripts/get_abi.py
 F:	scripts/kernel-doc*
 F:	scripts/lib/abi/*
 F:	scripts/lib/kdoc/*