clocksource/drivers/gemini: Rename Gemini timer to Faraday

After some research it turns out that the "Gemini" timer is
actually a generic IP block from Faraday Technology named
FTTMR010, so as to not make things too confusing we need to
rename the driver and its symbols to make sense.

The implementation remains the same in this patch but we fix
the copy-paste error in the timer name "nomadik_mtu" as we're
at it.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>