sgi/install_prerequisites.sh: fix failure to install cmake

The cmake installation fails due to unmet dependencies. Fix these
dependencies.

Suggested-by: Artem Kopotev <artem.kopotev@arm.com>
Signed-off-by: Thomas Abraham <thomas.abraham@arm.com>
Change-Id: I3de2d935a2450c7daead077bfdfb59e41cfecc48