drivers: clean-up prom.h implicit includes

Powerpc is a mess of implicit includes by prom.h. Add the necessary
explicit includes to drivers in preparation of prom.h cleanup.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Grant Likely <grant.likely@linaro.org>
diff --git a/drivers/edac/cell_edac.c b/drivers/edac/cell_edac.c
index c2eaf33..9ee1c76 100644
--- a/drivers/edac/cell_edac.c
+++ b/drivers/edac/cell_edac.c
@@ -15,6 +15,7 @@
 #include <linux/platform_device.h>
 #include <linux/stop_machine.h>
 #include <linux/io.h>
+#include <linux/of_address.h>
 #include <asm/machdep.h>
 #include <asm/cell-regs.h>