ml-apps: Add build and run support for VSI as audio source

This commit is meant to enable the users to build and run
keyword-detection and speech-recognition ML applications
using VSI(Virtual Streaming Interface) as the input audio
source.

`core_clk.mul=200000000` clock rate multiplier FVP option
is added to increase the clock rate which result in faster
and more precise ML inference.

Signed-off-by: Ahmed Ismail <Ahmed.Ismail@arm.com>