scripts/get_abi.pl: ignore some temp files

scripts/get_abi.pl: ignore some temp files

When there are filenames of the form ".orig" or ".rej" in
the Documenatation/ABI/ subdirectories, there can be confusing or
erroneous output generated. Example: the file
Documenation/ABI/testing/sysfs-bus-papr-pmem.orig causes this
warning message:

Documentation/ABI/testing/sysfs-bus-papr-pmem:2: WARNING: unknown document: '/powerpc/papr_hcalls'

Prevent this by skipping over filenames that may be created by
patch/diff tools etc.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Acked-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231228233113.5218-1-rdunlap@infradead.org