firmware: ti_sci: Drop unused structure ti_sci_rm_type_map

struct ti_sci_rm_type_map is no longer used. Drop its definition and its
declarations.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20200806074826.24607-3-lokeshvutla@ti.com