powerpc: export of_get_ibm_chip_id function

Export the of_get_ibm_chip_id() function. This will be used by the
PowerNV NX-842 driver.

Signed-off-by: Dan Streetman <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

arch/powerpc/kernel/prom.c

···
 	}
 	return -1;
 }
+EXPORT_SYMBOL(of_get_ibm_chip_id);
 
 /**
  * cpu_to_chip_id - Return the cpus chip-id