cpufreq: move freq change notifications to cpufreq core

Most of the drivers do following in their ->target_index() routines:

	struct cpufreq_freqs freqs;
	freqs.old = old freq...
	freqs.new = new freq...

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);

	/* Change rate here */

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

This is replicated over all cpufreq drivers today and there doesn't exists a
good enough reason why this shouldn't be moved to cpufreq core instead.

There are few special cases though, like exynos5440, which doesn't do everything
on the call to ->target_index() routine and call some kind of bottom halves for
doing this work, work/tasklet/etc..

They may continue doing notification from their own code as flag:
CPUFREQ_ASYNC_NOTIFICATION is already set for them.

All drivers are also modified in this patch to avoid breaking 'git bisect', as
double notification would happen otherwise.

Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Russell King <linux@arm.linux.org.uk>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/dbx500-cpufreq.c

@@ -22,28 +22,8 @@ static struct clk *armss_clk;
 static int dbx500_cpufreq_target(struct cpufreq_policy *policy,
 				unsigned int index)
 {
-	struct cpufreq_freqs freqs;
-	int ret;
-
-	freqs.old = policy->cur;
-	freqs.new = freq_table[index].frequency;
-
-	/* pre-change notification */
-	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
-
 	/* update armss clk frequency */
-	ret = clk_set_rate(armss_clk, freqs.new * 1000);
-
-	if (ret) {
-		pr_err("dbx500-cpufreq: Failed to set armss_clk to %d Hz: error %d\n",
-		       freqs.new * 1000, ret);
-		freqs.new = freqs.old;
-	}
-
-	/* post change notification */
-	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
-
-	return ret;
+	return clk_set_rate(armss_clk, freq_table[index].frequency * 1000);
 }
 
 static unsigned int dbx500_cpufreq_getspeed(unsigned int cpu)