watchdog: tegra_wdt: Use watchdog_stop_on_unregister and other improvements

Use watchdog_stop_on_unregister() in probe instead of calling
tegra_wdt_stop() in the remove function. Also introduce local variable
'struct device *dev' and use it instead of dereferencing it repeatedly.
Finally, drop the now empty remove function.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts
used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches



Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>