net: fix env flags for eth10addr and above

net: fix env flags for eth10addr and above

With CONFIG_REGEX enabled, ETHADDR_WILDCARD is set up for up to 10
interfaces (0..9) as the number can only have one digit.

On boards with more than 10 interfaces, this leads to the protection
and format checks being absent for eth10addr and above.

Fix this by changing ETHADDR_WILDCARD from "\\d?" to "\\d*" to allow
more than one digit.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>