drm/panfrost: Set HW_FEATURE_AARCH64_MMU feature flag on Bifrost models

Mali Bifrost MMU support AArch64 4kB page tables. This feature is in
panfrost based the HW_FEATURE_AARCH64_MMU feature flag.

Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>