cosmetic: serial: Fix typo in comment

Change-Id: I5d4901e01af477ebb815f70a5326ada6224c4be8
diff --git a/src/serial.c b/src/serial.c
index 31cb81d..4dcca08 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -67,7 +67,7 @@
 		return -errno;
 	}
 
-	/* now put it into blcoking mode */
+	/* now put it into blocking mode */
 	flags = fcntl(fd, F_GETFL, 0);
 	if (flags < 0) {
 		dbg_perror("fcntl get flags");