Some laptop models need to have different keycodes assigned to hotkey
scancodes.  Change the sparse keymap upon a DMI match, before the hotkey
input device is setup.

Instead of using three different callbacks in the DMI match table,
simplify code by using the driver_data field of struct dmi_system_id to
supply the requested keymap to a common callback.  Also merge keymaps
for S6410 and S6420 as they are identical.

Rename fujitsu_dmi_table to fujitsu_laptop_dmi_table to emphasize it is
no longer used by the backlight part of fujitsu-laptop.  Adjust
whitespace to make checkpatch happy.
Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Jonathan Woithe <jwoithe@just42.net>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>