diag: dci: Prevent using uninitialized variables

Presently chance of using uninitialized variables if a dci
command is not found is avoided by initializing command
structure variables.

Change-Id: I190299917ea6c7fadfc7686d43a7da098e0bc05e
Signed-off-by: Manoj Prabhu B <bmanoj@codeaurora.org>