powerpc/watchdog: improve watchdog comments

[Michael Ellerman]

On Wed, 2017-11-01 at 00:27:33 UTC, Nicholas Piggin wrote:
> The overview comments in the powerpc watchdog are out of date after
> several iterations and changes of the code. Bring them up to date.
> 
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/723b113319baa8d8b5f619a94348fa

cheers