Fix typos

Change-Id: I20745d5f30f9577622e27abf2f45220f026f65ac
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/28206
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

serial.c

@@ -194,7 +194,7 @@ int serialport_config(fdtype fd, int baud)
 				return 1;
 			}
 			/* We want whatever the termios looks like now, so the rest of the
-			   setup doesnt mess up the custom rate. */
+			   setup doesn't mess up the custom rate. */
 			if (tcgetattr(fd, &wanted) != 0) {
 				/* This should pretty much never happen (see above), but.. */
 				msg_perr_strerror("Could not fetch serial port configuration: ");