Input: mms114 - fix license module information

The driver has been released with GNU Public License v2 as stated
in the header, but the module license information has been tagged
as "GPL" (GNU Public License v2 or later).

Fix the module license information so that it matches the one in
the header as "GPL v2".

Fixes: 07b8481d ("Input: add MELFAS mms114 touchscreen driver")
Reported-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>