scripts: get_abi.pl: ignore some sysfs nodes earlier

When checking for undefined symbols, some nodes aren't easy
or don't make sense to be checked right now. Prevent allocating
memory for those, as they'll be ignored anyway.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/5228789cbef8241d44504ad29fca5cab356cdc53.1632411447.git.mchehab+huawei@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>