drivers/misc: add message to trace min_enc_lvl changes for debug

Add a message to trace the min_enc_lvl value changes to debug issues
related to hdcp secure content playback.

Change-Id: I1f21d723fda1156e175b9e2a6c325388745fd1ee
Signed-off-by: Sankeerth Billakanti <sbillaka@codeaurora.org>