eeepc-laptop: Prevent a panic when disabling RT2860 wireless when associated

This works around what I think is actually a bug in rt2860sta which is
triggered when the hardware "disappears" from beneath the driver, i.e. when
wireless is toggled off via ACPI. It does so by ensuring that the rfkill
soft-block flag is set before the hardware is disabled.

I do not know whether this patch is required if rt2800pci is in use instead
of rt2860sta; at the time of submission of this patch, I've not been able to
test this.

(Ref. http://bugzilla.kernel.org/show_bug.cgi?id=13390)

Signed-off-by: Darren Salt <linux@youmustbejoking.demon.co.uk>
Signed-off-by: Len Brown <len.brown@intel.com>