platform/x86: thinkpad_acpi: Add mappings for adaptive kbd clipping-tool and cloud keys

The X1 carbon 2014 / 2nd gen's adaptive keyboard top row's "Home" mode,
which is 1 of the 2 modes Linux supports, has clipping-tool and cloud
buttons which so far are not mapped.

I assume these were left as KEY_RESERVED because no suitable KEY_FOO codes
were available when support was added.

In the mean time we have gotten KEY_SELECTIVE_SCREENSHOT and this has been
used for the clipping-tool function under Fn + PrtSc on more traditional
ThinkPad keyboards already.

Finding a KEY_FOO code for the cloud key is harder looking at the symbol
it seems to refer to cloud-storage which made me think of file syncing,
or file transfer which has let me to pick KEY_XFER for this.

Note this is based on looking at a picture of the adaptive top row
in Home mode and has not been tested on an actual adaptive keyboard.

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/20240424122834.19801-21-hdegoede@redhat.com