juno/soc_clock_ram: Trust the HAL in mod_clock_drv_api

This driver implements an API defined by the HAL, so
we can be sure that the parameters passed to us do
not need to be sanitized.

Change-Id: I510c8d66b2919ef3814e5d8ea70a71bb04082968
Signed-off-by: Nicola Mazzucato <nicola.mazzucato@arm.com>