reset: simple: remove ZTE details in Kconfig help

The ZTE platform support in the simple reset driver has been
removed but the comment in the help wasn't removed so clean
this up too.

Fixes: 89d4f98a

 ("ARM: remove zte zx platform")
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210821094528.294579-1-pbrobinson@gmail.com


Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>