PM / OPP: rename data structures to dev_pm equivalents

Since Operating Performance Points (OPP) data structures are specific
to device specific power management, be specific and rename opp_* data
structures in OPP library with dev_pm_opp_* equivalent.

Affected structures are:
 struct opp
 enum opp_event

Minor checkpatch warning resulting of this change was fixed as well.

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>
diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index c5e31d2..f057d42 100644
--- a/drivers/cpufreq/omap-cpufreq.c
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -65,7 +65,7 @@
 	unsigned int i;
 	int r, ret = 0;
 	struct cpufreq_freqs freqs;
-	struct opp *opp;
+	struct dev_pm_opp *opp;
 	unsigned long freq, volt = 0, volt_old = 0, tol = 0;
 
 	if (!freq_table) {