redhat/configs: Disable CONFIG_X86_KERNEL_IBT

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2090231


Upstream Status: RHEL-only

As we are not backporting the complete set of X86_KERNEL_IBT patches,
we can't enable it at the moment.

Signed-off-by: Waiman Long <longman@redhat.com>