watchdog: gemini/ftwdt010: rename driver and symbols

This renames all the driver files and symbols for the Gemini
watchdog to FTWDT010 as it has been revealed that this IP block
is a generic watchdog timer from Faraday Technology used in
several SoC designs.

Select this driver by default for the Gemini, it is a sensible
driver to always have enabled.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>