Add voltage change delays to dediprog driver

Some investigations have shown that the original dediprog driver waits
about 200ms after setting voltage up and before setting voltage down.
This patch adds those delays. It helps flash chips to come up in time.

Corresponding to flashrom svn r1544.

Signed-off-by: Nico Huber <nico.huber@secunet.com>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/dediprog.c b/dediprog.c
index df8af61..cdd27b0 100644
--- a/dediprog.c
+++ b/dediprog.c
@@ -131,6 +131,10 @@
 	msg_pdbg("Setting SPI voltage to %u.%03u V\n", millivolt / 1000,
 		 millivolt % 1000);
 
+	if (voltage_selector == 0) {
+		/* Wait some time as the original driver does. */
+		programmer_delay(200 * 1000);
+	}
 	ret = usb_control_msg(dediprog_handle, 0x42, 0x9, voltage_selector,
 			      0xff, NULL, 0x0, DEFAULT_TIMEOUT);
 	if (ret != 0x0) {
@@ -138,6 +142,10 @@
 			 voltage_selector);
 		return 1;
 	}
+	if (voltage_selector != 0) {
+		/* Wait some time as the original driver does. */
+		programmer_delay(200 * 1000);
+	}
 	return 0;
 }