Fixing the GVM suspend failure due to veth_ipa_suspend

veth_ipa_suspend function returning an error when the interface
is already in deactivated is fixed. Changed the return
value from -EPERM to non error as there is no error in this case.

Change-Id: I10f283e767a442e6897c4d35cc370bbc84dd2d9d
Acked-by: Sarosh Hasan <sarohasa@qti.qualcomm.com>
Signed-off-by: Bojun Pan <bojunp@codeaurora.org>