Coverity: Refine outdated python scripts

This patch makes the following changes:
1. Remove the deprecated approach to download Coverity tool.
2. Update outdated descriptions to align with the latest Coverity job.
3. Print the coverage data after the long list of analyzed/un-analyzed
   files to make the log eaier to read.

Signed-off-by: Xinyu Zhang <xinyu.zhang@arm.com>
Change-Id: Id85e598f24e96d01c5f98305d36ab5af843ad9e0
1 file changed