firmware: arm_scmi: Set clock latency to U32_MAX if it is not supported

firmware: arm_scmi: Set clock latency to U32_MAX if it is not supported

As per the spec, the clock_enable_delay is the worst case latency
incurred by the platform to enable the clock. The value of 0 indicates
that the platform doesn't support the same and must be considered as
maximum latency for practical purposes.

Currently the value of 0 is assigned as is and is propogated to the clock
framework which can assume that the clock can support atomic enable operation.

Link: https://lore.kernel.org/r/20220428122913.1654821-1-sudeep.holla@arm.com
Fixes: 18f295b758b2 ("firmware: arm_scmi: Add support for clock_enable_latency")
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>