etc/usr/rc: fix argument passing for net drivers
etc/usr/rc: fix argument passing for net drivers

The expected argument name would include the instance number, which
is not only redundant in many cases (FOOETHn_n=arg.., "n" being the
instance number) and conflicted with what netconf(8) does, but some
drivers need to be able to see the arguments for all instances of its
driver type--for example, dp8390 needs to know how many earlier
instances have been configured to use PCI.

Change-Id: I4830b823352722f554a032979464aba8b08fc166

veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi