A return value of 0 from Python-level `ioctl()` means success, but if
that's returned unconditionally it means that the method supports all
ioctl calls, which is not true. Returning 0 without doing anything can
potentially lead to a crash, eg for MP_STREAM_SEEK which requires returning
a value in the passed-in struct pointer.
This commit makes it so that all `ioctl()` methods respond only to
MP_STREAM_CLOSE, ie they return -1 (indicating error) for all other ioctl
calls.
Signed-off-by: Damien George <damien@micropython.org>
a3128f89cc