diag: Fix get event mask command response

Currently, the response to the get event mask command returns
all 0's in its mask portion of the response. Fix the get event
mask response so that it returns the correct data.

Change-Id: Ie398e6a5c77c47aea10c05b9a5a28508559b2556
Signed-off-by: Dixon Peterson <dixonp@codeaurora.org>