objtool: Propagate early errors

objtool: Propagate early errors

If objtool runs into a problem that causes it to exit early, the overall
tool still returns a status code of 0, which causes the build to
continue as if nothing went wrong.

Note this only affects early errors, as later errors are still ignored
by check().

Fixes: b51277eb9775 ("objtool: Ditch subcommands")
Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
Link: https://lore.kernel.org/r/cb6a28832d24b2ebfafd26da9abb95f874c83045.1696355111.git.aplattner@nvidia.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>