usb_wwan driver continues pushing rx data buffer to tty node even if it is removed during device disconnect. This may cause watchdog bark as driver unnecessarily loops through the list of rx buffers and tries to push it to tty layer while holding spin lock with interrupts disabled. CRs-Fixed: 377066 Change-Id: I5569a4948aba89fd1d0d8ea5e8910ce2e0c8e917 Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>