powerpc/powernv: only register log if OPAL supports doing so

Correct use of REGISTER/UNREGISTER is to check if the token exists
before calling. If we don't we get a "OPAL: Called with bad token 101 !"
error, which is harmless but may be alarming to some.
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Acked-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/opal.c

@@ -665,6 +665,9 @@ static void __init opal_dump_region_init(void)
 	uint64_t size;
 	int rc;
 
+	if (!opal_check_token(OPAL_REGISTER_DUMP_REGION))
+		return;
+
 	/* Register kernel log buffer */
 	addr = log_buf_addr_get();
 	if (addr == NULL)
@@ -823,6 +826,7 @@ void opal_shutdown(void)
 	}
 
 	/* Unregister memory dump region */
+	if (opal_check_token(OPAL_UNREGISTER_DUMP_REGION))
 		opal_unregister_dump_region(OPAL_DUMP_REGION_LOG_BUF);
 }