Replace native calls in serprog with wrapper calls

Read(), write(), usleep() are replaced.

Corresponding to flashrom svn r1663.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Signed-off-by: Idwer Vollering <vidwer@gmail.com>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/serial.c b/serial.c
index 8e27aa0..05f853e 100644
--- a/serial.c
+++ b/serial.c
@@ -354,7 +354,7 @@
 			return 1;
 		}
 		if (!tmp)
-			msg_pdbg("Empty read\n");
+			msg_pdbg2("Empty read\n");
 		readcnt -= tmp;
 		buf += tmp;
 	}