cfg: Don't check BS TAP IDCODE in STM32 configs

cfg: Don't check BS TAP IDCODE in STM32 configs

Instead of updating these regularly we can just accept any IDCODE for the
boundary scan TAP.

The only downside might be that it's not immediately obvious if you
source a config for the wrong type of STM32.

Change-Id: I96d4d81699a491b3a46de3f0d3fd078ffddad4e4
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/3385
Tested-by: jenkins