libs/wlgen/wlgen/rta: fix calibration after rtapp refactoring
libs/wlgen/wlgen/rta: fix calibration after rtapp refactoring

Periodic workloads were promoted to Class status after Patrick's rtapp
refactoring.

Change RTA calibration accordingly.

Signed-off-by: Juri Lelli <bdc6bcd4e8b34b4b92413d758024aeca6da0e459@arm.com>

mdigiorgio/lisa,ARM-software/lisa,credp/lisa,bjackman/lisa,credp/lisa,bjackman/lisa,joelagnel/lisa,joelagnel/lisa,JaviMerino/lisa,ARM-software/lisa,ARM-software/lisa,ARM-software/lisa,credp/lisa,arnoldlu/lisa,mdigiorgio/lisa,arnoldlu/lisa,credp/lisa