cpufreq: intel_pstate: Fix static checker warning for epp variable

Fix warning for:
drivers/cpufreq/intel_pstate.c:731 store_energy_performance_preference()
error: uninitialized symbol 'epp'.

This warning is for a case, when energy_performance_preference attribute
matches pre defined strings. In this case the value of raw epp will not
be used to set EPP bits in MSR_HWP_REQUEST. So initializing with any
value is fine.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/intel_pstate.c

@@ -709,7 +709,7 @@ static ssize_t store_energy_performance_preference(
 	struct cpudata *cpu_data = all_cpu_data[policy->cpu];
 	char str_preference[21];
 	bool raw = false;
-	u32 epp;
+	u32 epp = 0;
 	int ret;
 
 	ret = sscanf(buf, "%20s", str_preference);