COMPMID-417 Minor documentation fixes and error handling in instruments

Fixed some Doxygen issues in the introduction and tests sections
Switched MaliCounter to use ARM_COMPUTE_ERROR in order to get more context in case of failure
Switched to use ARM_COMPUTE_ERROR instead of ERROR_ON in PMU and MaliCounter so that checks work in release mode too. (As these checks are to detect platform issues rather than programming errors)

Change-Id: Ibbefa5a87d93c5c3aa5e190680052e4e99987dfe
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/89662
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
6 files changed