doc: cmake and minor documentation corrections
Created by: tgonzalezorlandoarm
As using Make is deprecated,update the documentation accordingly so that only the CMake build system, commands and dependencies are mentioned. This commit also updates some minor changes/errors in documentation.
Signed-off-by: Tomás Agustín González Orlando tomasagustin.gonzalezorlando@arm.com Change-Id: I563d9ee343b4ab07c4e0d8d4845b8b574b31dde0