[POWERPC] Add common clock setting routine mpc52xx_psc_set_clkdiv()

PSC drivers should not access the CDM registers directly.  Instead provide
a common routine for setting the PSC clock parameters with the required
locking.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/powerpc/platforms/52xx/efika.c b/arch/powerpc/platforms/52xx/efika.c
index a0da70c..a2068fa 100644
--- a/arch/powerpc/platforms/52xx/efika.c
+++ b/arch/powerpc/platforms/52xx/efika.c
@@ -180,6 +180,9 @@
 {
 	rtas_initialize();
 
+	/* Map important registers from the internal memory map */
+	mpc52xx_map_common_devices();
+
 	efika_pcisetup();
 
 #ifdef CONFIG_PM