SST: Update CMakeLists.inc and documentation

This patch updates CMakeLists.inc to print out information
about the SST flags selected in cmake execution phase.
It also adds a missing check for SST_ENABLE_PARTIAL_ASSET_RW
and updates the SST integration guide to document
SST_ENABLE_PARTIAL_ASSET_RW flag.

Change-Id: I5dd71d37380da2365daa3c8295c3c4d00cd2c09a
Signed-off-by: Marc Moreno <marc.morenoberengue@arm.com>
3 files changed