Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

SGI-IP28 is running in so called slow mode, when kernel is started
from the PROM. PROM calls must be done in slow mode otherwise the
PROM will issue an error. To get better memory performance we now
switch to normal mode, when the PROM is no longer needed.
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

None of weakly ordered processor supported in tree need this but it seems
like this could change ...
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Also the R4000 / R4600 LL/SC instructions imply a sync so no explicit sync
needed.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>