iris: Allow shared scanout buffer to be placed in smem as well

iris: Allow shared scanout buffer to be placed in smem as well

i915 and Xe kmd allows scanout to display of prime buffers placed
in smem.

Allowing shared and scanout bos to be placed in smem and lmem allows
the dma buf to work in some cases that only lmem is not enough.

Fixes: c10ff1970461 ("iris: Place scanout buffers only into lmem for discrete GPUs")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/8867
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/8766
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Tested-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22665>