sgi/pre-reqs: add script to install prerequisite packages for SGI platform

To build and execute the SGI platform software, certain host OS packages are
expected to be pre-installed. This script helps with installing the required
host packages.

Change-Id: Ib7a9639b7722426c57b68e1b19a25d406c342047
Signed-off-by: Lokesh Belathur Veerappa <lokesh.belathurveerappa@arm.com>