nvmem: meson-efuse: add peripheral clock

Get and enable the peripheral clock required by the efuse device.
The driver has been handle to work without it so far because the
clock was left enabled by default but it won't be the case soon.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>