cfg: fix incorrect STM32L SW-DP id

STM32L ref manual (RM00038 Rev5) states the SW-DP id should be 0x4ba00477.
The correct value from silicon is 0x2ba01477 - the typo has been confirmed by ST.

Change-Id: Ie35a1f13dc5dedc1b148fb219c6974bfa48b537c
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/441
Tested-by: jenkins
Reviewed-by: Peter Stuge <peter@stuge.se>

tcl/target/stm32lx_stlink.cfg

@@ -3,7 +3,7 @@
 #
 
 set CHIPNAME stm32lx
-set CPUTAPID 0x4ba00477
+set CPUTAPID 0x2ba01477
 set WORKAREASIZE 0x3800
 
 source [find target/stm32_stlink.cfg]