platform/x86: thinkpad_acpi: Do hkey to scancode translation later

platform/x86: thinkpad_acpi: Do hkey to scancode translation later

Modify hotkey_notify_hotkey() and it helpers to mostly directly operate
on hkey codes (TP_HKEY_EV_* returned by "MHKP") instead of on the 0 -
TPACPI_HOTKEY_MAP_LEN scancodes used for scancode -> keycode translation.

Keeping things in the hkey format as long a possible is a bit cleaner and
this patch prepares things for moving to sparse-keymaps.

Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240424122834.19801-7-hdegoede@redhat.com