SH boards in general only wire this up in 8 or 16-bit mode, and
as we never had the wrappers for 32-bit mode defined, SMC_CAN_USE_32BIT
caused build failure for the non-Solution Engine boards. This gets it
building again.
Also kill off the straggling set_irq_type() definition, this is left
over cruft that was missed when the rest of it switched to IRQ flags.
Signed-off-by: Paul Mundt <lethal@xxxxxxxxxxxx>