diag: Command registration not happening properly

Some CM command registrations are not happening properly
on apps side. This could be because some smd events
for control type were getting missed. Make changes
in order to read pending SMD packets for control
type.

Change-Id: I0fe25455275f6169bee91d151d8657330081c104
CRs-Fixed: 516718
Signed-off-by: Mohit Aggarwal <maggarwa@codeaurora.org>
Merge "diag: Command registration not happening properly"