Up until now, the report descriptor template parameter IDs were only
used with pen report descriptors and they were named accordingly.

Rename the enum and the total number of IDs to make them interface
agnostic.

Refactor, no functional changes.
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>