dmaengine: ti: k3-psil: fix deadlock on error path

The mutex_unlock() is missed on error path of psil_get_ep_config()
which causes deadlock, so add missed mutex_unlock().

Fixes: 8c6bb62f ("dmaengine: ti: k3 PSI-L remote endpoint configuration")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20200408185501.30776-1-grygorii.strashko@ti.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/ti/k3-psil.c

@@ -27,6 +27,7 @@ struct psil_endpoint_config *psil_get_ep_config(u32 thread_id)
 			soc_ep_map = &j721e_ep_map;
 		} else {
 			pr_err("PSIL: No compatible machine found for map\n");
+			mutex_unlock(&ep_map_mutex);
 			return ERR_PTR(-ENOTSUPP);
 		}
 		pr_debug("%s: Using map for %s\n", __func__, soc_ep_map->name);