lima: remove lima_ctx_buff_va submit flags (v2)

lima: remove lima_ctx_buff_va submit flags (v2)

We don't have any shared lima_ctx_buff for both GP and PP,
so no need to have these flags.

v2:
still add submit in lima_ctx_buff_va because some bo need
to exist cross flush, so not every submit will call
lima_ctx_buff_alloc.

Reviewed-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3755>