tcl/target: Use vectreset for CC13xx/CC26xx targets.

tcl/target: Use vectreset for CC13xx/CC26xx targets.

nSRST and sysreqreset are both broken for these targets. Upon a
hard reset, the target disables the TDO/TDI pins and the
ICEPick router will remove the target's TAP from the scan
chain. The scripts to do these tasks are run, but then
OpenOCD throws the reset again breaking the debug connection.

Until that issue can be resolved, vectreset is the only
reset that works without breaking the debug connection.

Update: original patch didn't have the correct reset command.

Change-Id: If7c985b703c87399a13364609d370d6222f4a66c
Signed-off-by: Edward Fewell <efewell@ti.com>
Reviewed-on: http://openocd.zylin.com/5511
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>