remove hal watchdog stop, as many platforms don't provide the ability to stop a watchdog, so the OS must have intrinisic mechanisms for tickling.
remove hal watchdog stop, as many platforms don't provide the ability to stop a watchdog, so the OS must have intrinisic mechanisms for tickling.

andrzej-kaczmarek/incubator-mynewt-core,wes3/incubator-mynewt-core,mlaz/mynewt-core,wes3/incubator-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,wes3/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,wes3/incubator-mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,wes3/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,IMGJulian/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,mlaz/mynewt-core