linux-imx

clocksource/drivers/riscv: Change name riscv_timer to timer-riscv

In order to unify the names in this directory, let's rename the driver to be
prefixed with timer-*

Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>