tcl: Add default hooks for STM32F3x

tcl: Add default hooks for STM32F3x

Keep clocks running in low power modes. Stop watchdogs from interfering
with the debug session. Set up PLL and increase clock at reset init.

Change-Id: I984d2018f7d47a1042f1e12894563154fa7b566c
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/2196
Tested-by: jenkins
Reviewed-by: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>