cortex_m: Do additional initialization during reset

cortex_m: Do additional initialization during reset

SAM4L requires additional steps to be taken right after SYSRESETREQ is
issued in order to function robustly:

       - CMSIS-DAP DAP driver needs to explicitly check for sticky bit
         errors since it is possible for adapter to perform successful
         write opration, report no errors and then, under the hood, do
         some other things that will result in sticky bit being set.

       - Debugger needs to wait for security system to finish
         intialization and assert CDBGPWRUPACK before proceeding

This change is related to commit http://openocd.zylin.com/#/c/1995/

Change-Id: I741c95a809bfd60d930cec9482239e4796a62326
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-on: http://openocd.zylin.com/2088
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-by: Andrey Yurovsky <yurovsky@gmail.com>