jtag/adapter: add connect_[de]assert_srst to reset_config usage

Add the connect under reset options to the online help for
reset_config.

Change-Id: I4b9a87b234de01531390b39b898a848841d1e834
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/1377
Tested-by: jenkins
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>