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>


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37988 3c298f89-4303-0410-b956-a3cf2f4a3e73