media: v4l2-ctrls: allow V4L2_CTRL_TYPE_BUTTON with request api

remove check for V4L2_CTRL_TYPE_BUTTON from
v4l2_ctrl_request_clone and v4l2_ctrl_request_setup().

Signed-off-by: Dikshita Agarwal <dikshita@codeaurora.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>