Input: mms114 - add SPDX identifier

Replace the original license statement with the SPDX identifier.
Add also one line of description as recommended by the COPYING
file.

Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>