cpufreq: Prepare cleanup of powerpc's asm/prom.h

powerpc's asm/prom.h brings some headers that it doesn't
need itself.

In order to clean it up, first add missing headers in
users of asm/prom.h
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/pasemi-cpufreq.c

@@ -18,7 +18,6 @@
 
 #include <asm/hw_irq.h>
 #include <asm/io.h>
-#include <asm/prom.h>
 #include <asm/time.h>
 #include <asm/smp.h>
 

drivers/cpufreq/pmac32-cpufreq.c

@@ -24,7 +24,7 @@
 #include <linux/device.h>
 #include <linux/hardirq.h>
 #include <linux/of_device.h>
-#include <asm/prom.h>
+
 #include <asm/machdep.h>
 #include <asm/irq.h>
 #include <asm/pmac_feature.h>

drivers/cpufreq/pmac64-cpufreq.c

@@ -22,7 +22,7 @@
 #include <linux/completion.h>
 #include <linux/mutex.h>
 #include <linux/of_device.h>
-#include <asm/prom.h>
+
 #include <asm/machdep.h>
 #include <asm/irq.h>
 #include <asm/sections.h>

drivers/cpufreq/ppc_cbe_cpufreq.c

@@ -12,7 +12,6 @@
 #include <linux/of_platform.h>
 
 #include <asm/machdep.h>
-#include <asm/prom.h>
 #include <asm/cell-regs.h>
 
 #include "ppc_cbe_cpufreq.h"

drivers/cpufreq/ppc_cbe_cpufreq_pmi.c

@@ -13,9 +13,9 @@
 #include <linux/init.h>
 #include <linux/of_platform.h>
 #include <linux/pm_qos.h>
+#include <linux/slab.h>
 
 #include <asm/processor.h>
-#include <asm/prom.h>
 #include <asm/pmi.h>
 #include <asm/cell-regs.h>