mpipl: Disable fast-reboot during post MPIPL boot

Otherwise device tree will continue to have `mpipl-boot` and kernel may
think its MPIPL boot.

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Reviewed-by: Stewart Smith <stewart@flamingspork.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>

core/opal-dump.c

@@ -529,6 +529,8 @@ void opal_mpipl_init(void)
 	mpipl_metadata = (void *)(DUMP_METADATA_AREA_BASE);
 
 	if (dt_find_property(dump_node, "mpipl-boot")) {
+		disable_fast_reboot("MPIPL Boot");
+
 		post_mpipl_get_preserved_tags();
 		post_mpipl_get_opal_data();
 		post_mpipl_arch_regs_data();