core/serial: Fix typo

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/src/serial.c b/src/serial.c
index b68fd56..e61edb7 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -185,7 +185,7 @@
 	unsigned int speed = baudrate;
 	rc = ioctl(fd, IOSSIOSPEED, &speed);
 	if (rc < 0) {
-		dbg.perror("ioctl(IOSSIOSPEED)");
+		dbg_perror("ioctl(IOSSIOSPEED)");
 		return -errno;
 	}
 	return 0;