scripts: get_abi.pl: stop check loop earlier when regex is found

Right now, there are two loops used to seek for a regex. Make
sure that both will be skip when a match is found.

While here, drop the unused $defined variable.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/2ba722d2cdbe7c7d0f1d1b58d350052576d1d703.1632411447.git.mchehab+huawei@kernel.org


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