surface pro 3: Add support driver for Surface Pro 3 buttons

Since Surface Pro 3 does not follow the specs of "Windows ACPI Design
Guide for SoC Platform", code in drivers/input/misc/soc_array.c can
not detect these buttons on it. According to bios implementation,
Surface Pro 3 encapsulates these buttons in a device named "VGBI",
with _HID "MSHW0028". When any of the buttons is pressed, a specify
ACPI notification code for this button will be delivered to "VGBI". For
example, if power button is pressed down, ACPI notification code of 0xc6
will be sent by Notify(VGBI, 0xc6).

This patch leverages "VGBI" to distinguish different ACPI notification
code from Power button, Home button, Volume button, then dispatches these
code to input layer. Lid is already covered by acpi button driver, so
there's no need to rewrite.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=84651


Tested-by: Ethan Schoonover <es@ethanschoonover.com>
Tested-by: Peter Amidon <psa.pub.0@picnicpark.org>
Tested-by: Donavan Lance <tusklahoma@gmail.com>
Tested-by: Stephen Just <stephenjust@gmail.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
[dvhart@linux.intel.com: Formatting corrections in MAINTAINERS and Intel (c)]
Signed-off-by: Darren Hart <dvhart@linux.intel.com>