Add get and set accessors for jtag_speed:

- Setter calls the interface driver callback to improve core encapsulation.
- Use getter in standard JTAG interface drivers and ZY1000 minidriver.


git-svn-id: svn://svn.berlios.de/openocd/trunk@2159 b42882b7-edfa-0310-969c-e2dbd0fdcd60

src/jtag/jlink.c

@@ -340,7 +340,7 @@ static int jlink_init(void)
 	jlink_reset(0, 0);
 	jtag_sleep(3000);
 	jlink_tap_init();
-	jlink_speed(jtag_speed);
+	jlink_speed(jtag_get_speed());
 
 	/* v5/6 jlink seems to have an issue if the first tap move
 	 * is not divisible by 8, so we send a TLR on first power up */