cpufreq: Allow drivers to advertise boost enabled

The behavior introduced in commit f37a4d6b4a2c ("cpufreq: Fix per-policy
boost behavior on SoCs using cpufreq_boost_set_sw()") sets up the boost
policy incorrectly when boost has been enabled by the platform firmware
initially even if a driver sets the policy up.

This is because policy_has_boost_freq() assumes that there is a frequency
table set up by the driver and that the boost frequencies are advertised
in that table. This assumption doesn't work for acpi-cpufreq or
amd-pstate. Only use this check to enable boost if it's not already
enabled instead of also disabling it if alreayd enabled.

Fixes: f37a4d6b4a2c ("cpufreq: Fix per-policy boost behavior on SoCs using cpufreq_boost_set_sw()")
Link: https://patch.msgid.link/[e-mail]
Reviewed-by: Sibi Sankar <[e-mail]>
Reviewed-by: Dhruva Gole <[e-mail]>
Acked-by: Viresh Kumar <[e-mail]>
Reviewed-by: Gautham R. Shenoy <[e-mail]>
Suggested-by: Viresh Kumar <[e-mail]>
Suggested-by: Gautham R. Shenoy <[e-mail]>
Signed-off-by: Mario Limonciello <[e-mail]>
Cc: All applicable <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/cpufreq/cpufreq.c

···
 		}
 
 		/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
-		policy->boost_enabled = cpufreq_boost_enabled() && policy_has_boost_freq(policy);
+		if (cpufreq_boost_enabled() && policy_has_boost_freq(policy))
+			policy->boost_enabled = true;
 
 		/*
 		 * The initialization has succeeded and the policy is online.