slim: Initialize return-value in port-allocation API

-EINVAL is returned if number of ports requested is 0

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
diff --git a/drivers/slimbus/slimbus.c b/drivers/slimbus/slimbus.c
index 626bd8d..3b79129 100644
--- a/drivers/slimbus/slimbus.c
+++ b/drivers/slimbus/slimbus.c
@@ -953,7 +953,8 @@
 int slim_alloc_mgrports(struct slim_device *sb, enum slim_port_req req,
 				int nports, u32 *rh, int hsz)
 {
-	int i, j, ret;
+	int i, j;
+	int ret = -EINVAL;
 	int nphysp = nports;
 	struct slim_controller *ctrl = sb->ctrl;