kbuild, gpio: remove MODULE_LICENSE in non-modules

kbuild, gpio: remove MODULE_LICENSE in non-modules

Since commit 8b41fc4454e ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.

So remove it in the files in this commit, none of which can be built as
modules.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-unisoc@lists.infradead.org
Cc: linux-gpio@vger.kernel.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>