stlink: handle error bad-AP

The new firmwares for ST-Link support handling multiple AP, but
are (actually) limited to the AP number in range [0..8].
Any tentative to operate on AP number higher than 8 returns an
error "bad AP".
Add the error code and the related message.

Change-Id: I78a98b2612d10e580d03fc43ed9f2b09619d39d8
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/4981

Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Tested-by: jenkins

src/jtag/drivers/stlink_usb.c

@@ -167,6 +167,8 @@ struct stlink_usb_handle_s {
 #define STLINK_SWD_AP_STICKY_ERROR     0x19
 #define STLINK_SWD_AP_STICKYORUN_ERROR 0x1a
 
+#define STLINK_BAD_AP_ERROR            0x1d
+
 #define STLINK_CORE_RUNNING            0x80
 #define STLINK_CORE_HALTED             0x81
 #define STLINK_CORE_STAT_UNKNOWN       -1
@@ -751,6 +753,9 @@ static int stlink_usb_error_check(void *handle)
 		case STLINK_SWD_AP_STICKYORUN_ERROR:
 			LOG_DEBUG("STLINK_SWD_AP_STICKYORUN_ERROR");
 			return ERROR_FAIL;
+		case STLINK_BAD_AP_ERROR:
+			LOG_DEBUG("STLINK_BAD_AP_ERROR");
+			return ERROR_FAIL;
 		default:
 			LOG_DEBUG("unknown/unexpected STLINK status code 0x%x", h->databuf[0]);
 			return ERROR_FAIL;