sparcspkr: use sbus_*() primitives for IO

The memory are mapped using of_ioremap() which is
an indication this is sbus memory.
Shift all uses of inb/outb to the sbus variants.

The inb/outb methods uses ASI_PHYS_BYPASS_EC_E_L,
whereas sbus_ variants uses ASI_PHYS_BYPASS_EC_E.

The difference is if the reads/writes are done in
native or little endian.
But for byte reads/writes there is no difference
so this does not matter for inb/outb - and this
driver only uses the byte variants.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>