drivers: soc: qcom: initial support for plh scmi client driver

Add initial support for plh scmi client driver which registers
into scmi framework for plh vendor protocol extension.
Also registers with plh interface driver msm_performance.

Change-Id: I448a714486ff4c7ea38cbeeec1ddb5e183b76e65
Signed-off-by: Gaurav Singh <sgaurav@codeaurora.org>