The Gemini RTC is actually a generic IP block from Faraday
Technology names FTRTC010. Rename the driver file and all
symbols to match this IP name.

The relationship can be clearly seen in the U-Boot driver
posted by Po-Yu Chuang for the Faraday A320 board:
https://lists.denx.de/pipermail/u-boot/2009-September/061326.html

Remove the dependency on ARCH_GEMINI but select the driver
for ARCH_GEMINI so we get a smooth transition. The IP block
is synthsized on different silicon and architectures.

Cc: Po-Yu Chuang <ratbert@faraday-tech.com>
Acked-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>