Martin Kojtal authored Apr 29, 2022 and Wilfried Chauveau committed Jun 30, 2022

Same as we have in Open IoT SDK Readme, we show using -GNinja. This avoids an issue
on Windows, where the CMake default toolchain would be Visual Studio (not supported). The note comes from SDK as well.

A more advanced user can switch to other generators.

Signed-off-by: Martin Kojtal <martin.kojtal@arm.com>