scripts/get_abi.pl: Ignore hidden files

scripts/get_abi.pl: Ignore hidden files

get_abi.pl currently collects every file in Documentation/ABI. This
causes a UnicodeDecodeError in Documentation/sphinx/kernel_abi.py,
when it finds my Vim swap files (.foo.swp) in the directory.

To avoid such issues, ignore hidden files in get_abi.pl.

Reviewed-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20220129005019.2090996-1-j.neuschaefer@gmx.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>