diag: Queue the next read in case for usb connect event

Currently apps diag is not queueing the next read from
peripherals in case for usb connect event. This patch resolves
the issue.

Change-Id: I289826a6241d2930920275a8b0dd3a863e798095
Signed-off-by: Katish Paran <kparan@codeaurora.org>