kbuild: drop cpuinit/cpuexit checks in modpost

With the removal of cpuinit/cpuexit we no longer need to
do section mismatch checks on these sections.

Drop it from modpost.

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
cpuinit: turn __cpuinit into nops

    now that there's no users left, turn __cpuinit into a nop for now,
    to avoid breaking any in-flight code. In a few releases we can just
    drop it entirely.

    Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>