media: fdp1: Fix a memory leak bug

In fdp1_open(), 'ctx' is allocated through kzalloc(). However, it is not
deallocated if v4l2_ctrl_new_std() fails, leading to a memory leak bug. To
fix this issue, free 'ctx' before going to the 'done' label.

Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>