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.