openrisc: remove unnecessary prom.c includes

It appears openrisc prom.c was just copied from another arch with a
bunch of unnecessary includes. Remove all the unecessary ones.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: linux@lists.openrisc.net
1 file changed