stm32w: add STM32w108xx generic configuration

Add generic TCL configuration for STM STM108Wxx chips.

Change-Id: I981cdccb78833f442c3be4188c8c023064067e4e
Signed-off-by: Giuseppe Barba <giuseppe.barba@gmail.com>
Reviewed-on: http://openocd.zylin.com/1439
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>