ARM: dts: Add keypad support for droid 4

ARM: dts: Add keypad support for droid 4

Let's configure the keypad in a way where it's usable out of the
box for Linux console use. We want to have the keyboard usable with
Linux console for example when stuck into an initramfs during boot,
for when installing a distro.

As we need to need to have keys mapped in the user space anyways
for some of the keys to match the labels, this non-standard mapping
or usability should be OK.

Some keys don't match the labels either as they don't follow the PC
keyboard style. For example we have "shift + ," produce "<", and
"shift + ." produce ">" instead of ";" and ":".

So let's follow the standard PC keyboard layout for ctrl, shift and
alt keys:

Ctrl = what is labeled as shift
Alt = what is labeled as SYM
Shift = what is lableled as caps lock

This way we have Ctrl key for console use. Who knows where they got
the caps lock idea.. Probably from some focus group popularity vote
or something.

For the OK key, let's keep it as the useless KEY_OK unless we can
come up with some standard mapping for it we can stick with.

We have at least Esc, Delete, Meta, and Page Down keys missing, but
none of them seem to be better than others. PC keyboard often has
Page Down in that location. Esc would be probably the most usable
one when installing a Linux distro but is the opposite of OK.

Note that the LCD keys are just touchscreen hot spots, so I'm not
sure if the driver or hardware allows setting them up as keys for
the console.

Anyways, the rest can be mapped in the user space.

Cc: Marcel Partap <mpartap@gmx.net>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Scott <michael.scott@linaro.org>
Tested-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>