diag: Check correct status variable to send log mask

Diag driver was incorrectly checking the message mask status to
send the log mask control packet to the peripherals. This patch
checks the correct status variable to send the log mask to the
peripherals.

Change-Id: I6733c930e66cabc77c6cfe62b9aa7cd48b9fe13d
CRs-Fixed: 542074
Signed-off-by: Ravi Aravamudhan <aravamud@codeaurora.org>