qseecom: wipe_key failing

While wiping the keys from multiple crypto, it is wiping keys from
same crypto due to wrong loop variable. Fixed the issue by using
correct variable.

Change-Id: I8e7f9d3a773ff1809fe9b71d8e7bee75e789deca
Signed-off-by: Dinesh K Garg <dineshg@codeaurora.org>