dove: fix sdio workaround to config all sd gpio's as input

BugLink: http://bugs.launchpad.net/bugs/611634

the previous code configured only DATA1 gpio to be input, but this
was not enough, all pins must be configured as gpio input.

Signed-off-by: Eric Miao <eric.miao@canonical.com>
Signed-off-by: Brad Figg <brad.figg@canonical.com>