clocksource/drivers/fttmr010: Merge FTTMR010 DT bindings

This merges the Moxa and FTTMR010 device tree bindings into the
Faraday binding document to avoid confusion.

The FTTMR010 is the IP block used by these SoCs, in vanilla
or modified variant.

The Aspeed variant is modified such that it is no longer fully
register-compatible with FTTMR010 so for this reason it is not
listed with two compatible strings, instead just one.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>