drm/v3d: Fix double free in v3d_submit_cl_ioctl()

Originally this error path used to leak "bin" but then we accidentally
applied two separate commits to fix it and ended up with a double free.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20201026094905.GA1634423@mwanda