panfrost: Skip specifying in_syncs

panfrost: Skip specifying in_syncs

With the current kernel UABI, there is no benefit to explicitly
specifiying dependencies, since the kernel by design adds implicit
dependencies to any referenced BOs. This is something we'd like to
address in the future, but efficient handling with future kernels will
require a tweaked design in userspace as well. So let's do the obvious
thing now, and extend later.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5995>