serial: Reorder serial_assign()

Reorder serial_assign() function to get rid of the extra level of
indentation. Also, adjust the return value to be -EINVAL instead of
positive one to be more consistent.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Tom Rini <trini@ti.com>

drivers/serial/serial.c

@@ -26,6 +26,7 @@
 #include <stdio_dev.h>
 #include <post.h>
 #include <linux/compiler.h>
+#include <errno.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -205,13 +206,13 @@ int serial_assign(const char *name)
 	struct serial_device *s;
 
 	for (s = serial_devices; s; s = s->next) {
-		if (strcmp(s->name, name) == 0) {
-			serial_current = s;
-			return 0;
-		}
+		if (strcmp(s->name, name))
+			continue;
+		serial_current = s;
+		return 0;
 	}
 
-	return 1;
+	return -EINVAL;
 }
 
 void serial_reinit_all(void)