drivers: rmnet_shs: Fix failsafe timer

Failsafe timer would incorrectly never flush parked packets.
This fixes that so that after 1st flush it continues flushing
parked packets after a time limit.

CRs-Fixed: 2345169
Change-Id: Ia09708e884bbf3fa40b85981191a92283a0e8aa3
Acked-by: Raul Martinez <mraul@qti.qualcomm.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>