kernel: b53: use hard coded switch reset gpio on some boards.

The Linksys wrt310n v1 does not have a robo_reset config variable in
nvram, but GPIO Pin 8 is the pin needed for resetting the external
switch, Linksys hard coded it into their source code.

Thank you Devastator for testing.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

SVN-Revision: 37988