Stop duplicate printing of detected GPUs
The detected GPUs and their compatibility status are always printed to
both stderr and log file immediately after detection, as part of the
normal hardware report.
When the user made an invalid selection, we should not print the
information about the detected GPUs again (differently).
When an auto-selection is made, we do not need to print information
about the detected GPUs again.
sprint_gpus is now local to a single source file.
Noted TODO to separate a printing functionality from a checking
routine.
Change-Id: I47ef0da6bdf58d9a61b8577e539effd96c771b8c