powerpc/rtas: Unexport rtas_online_cpus_mask, rtas_offline_cpus_mask

These aren't used by modular code, nor should they be.

Fixes: 120496ac ("powerpc: Bring all threads online prior to migration/hibernation")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190718162214.5694-1-nathanl@linux.ibm.com

arch/powerpc/kernel/rtas.c

@@ -922,13 +922,11 @@ int rtas_online_cpus_mask(cpumask_var_t cpus)
 
 	return ret;
 }
-EXPORT_SYMBOL(rtas_online_cpus_mask);
 
 int rtas_offline_cpus_mask(cpumask_var_t cpus)
 {
 	return rtas_cpu_state_change_mask(DOWN, cpus);
 }
-EXPORT_SYMBOL(rtas_offline_cpus_mask);
 
 int rtas_ibm_suspend_me(u64 handle)
 {