dsp: fix total size in set ui property

Total size was incorrectly adjusted after determining
IID param size in SET_UI_PROPERTY. Fix total size with
correct APR packet and param sizes.

Change-Id: I5874b470811733e60b40cc240d4c0db995b30bac
Signed-off-by: Vikram Panduranga <vpandura@codeaurora.org>