clover: add support for drivers having no proper binary format

Most drivers have actually no binary format and just store the IR directly
as a single entry point blob.

v2: add a cap to switch between single or multi entry point binaries
v3: remove the entry_point field
v4: remove PIPE_CAP_MULTI_ENTRY_POINT_BINARIES
v5: remove supports_multiple_entry_points

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Pierre Moreau <pierre.morrow@free.fr>