diag: Increase max client limit

Currently, diag allows maximum 30 clients which is
exhausted and new clients are not able to open handle
with diag. This patch fixes this issue.

Change-Id: I1d016b1ed21c51b9282abc032d55bd87c94c0d8c
Signed-off-by: Mohit Aggarwal <maggarwa@codeaurora.org>