runqemu-ifup: fix tap index

runqemu-ifup: fix tap index

Recent patches changed the index of the tap interfaces. They start now
with tap1 instead of tap0. Also the IP address starts with 192.168.7.3
instead of 192.168.7.1. This gets reverted to the previous behavior.

Signed-off-by: Adrian Freihofer <adrian.freihofer@siemens.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>