PM / OPP: rename header to linux/pm_opp.h

Since Operating Performance Points (OPP) functions are specific
to device specific power management, be specific and rename opp.h
to pm_opp.h

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

arch/arm/mach-omap2/omap-pm.h

@@ -17,7 +17,7 @@
 #include <linux/device.h>
 #include <linux/cpufreq.h>
 #include <linux/clk.h>
-#include <linux/opp.h>
+#include <linux/pm_opp.h>
 
 /*
  * agent_id values for use with omap_pm_set_min_bus_tput():