Revert "ip_tunnels: use DEV_STATS_INC()"

This reverts commit e90e7034 which is
commit 9b271eba upstream.

It breaks the build due to a previous commit that was reverted for
Android ABI issues.  If this needs to be added, it can be done so in the
future in an abi-safe way.

Bug: 161946584
Change-Id: I016ca3ddfafde35fe1b91876d3e9536fdbd00320
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>