Revert "dell-laptop: Remove rfkill code"

Without rfkill functionality in dell-laptop I have the following problems:
-If the hardware radio switch is set to disable the radio, then userspace
 will still think it can use wireless and bluetooth.
-The wwan / 3g modem cannot be soft blocked without the dell-laptop rfkill
 functionality

I know the rfkill functionality was removed from the dell-laptop driver because
it caused more problems then it fixed, and the blacklist for it was growing out
of control.

But in the thread discussing this Dell mentioned that they only QA the rfkill
acpi interface on Latitudes and indeed there have been no blacklist entries
for Latitudes. Therefor I would like to bring the rfkill functionality back
only for Latitudes. This patch is a straight-forward revert. The next patch
in this set will drop the blacklist and replace it with a Latitude check.

This reverts commit a6c2390c

.

Conflicts:
	drivers/platform/x86/dell-laptop.c

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>