objtool: enable CONFIG_OBJTOOL_WERROR

JIRA: https://issues.redhat.com/browse/RHEL-85302

This patchset backports CONFIG_OBJTOOL_WERROR and supporting commits to rhel-9.

To minimize disruption, the promotion of objtool warnings to build errors will only occur for kernel and in-tree kernel builds. This means it will not be activated for (third party) out-of-tree kernel module builds.

Signed-off-by: Joe Lawrence joe.lawrence@redhat.com