tilegx: replace cpu_tilegx_init() with cpu_generic_init()

tilegx: replace cpu_tilegx_init() with cpu_generic_init()

cpu_tilegx_init() always falls back to TYPE_TILEGX_CPU object
regardless of cpu_model. Put fallback logic into
tilegx_cpu_class_by_name() which would translate any cpu_model
into TYPE_TILEGX_CPU class and replace cpu_tilegx_init()
with cpu_generic_init().

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <1503592308-93913-15-git-send-email-imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>