staging: fsl-mc/dpio: Propagate error code

dpaa2_io_service_register() returns zero even if
qbman_swp_CDAN_set() encountered an error. Fix this
by propagating the error code so the caller is informed
data availability notifications are not properly set
for a channel.
Signed-off-by: NIoana Radulescu <ruxandra.radulescu@nxp.com>
Acked-by: NBogdan Purcareata <bogdan.purcareata@nxp.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fsl-mc/bus/dpio/dpio-service.c

@@ -260,7 +260,7 @@ int dpaa2_io_service_register(struct dpaa2_io *d,
 
 	/* Enable the generation of CDAN notifications */
 	if (ctx->is_cdan)
-		qbman_swp_CDAN_set_context_enable(d->swp,
+		return qbman_swp_CDAN_set_context_enable(d->swp,
 							 (u16)ctx->id,
 							 ctx->qman64);
 	return 0;