cpufreq: brcmstb-avs-cpufreq: Fix resource leaks in ->remove()

If 'cpufreq_unregister_driver()' fails, just WARN and continue, so that
other resources are freed.

Fixes: de322e085995 ("cpufreq: brcmstb-avs-cpufreq: AVS CPUfreq driver for Broadcom STB SoCs")
Signed-off-by: Christophe JAILLET <[e-mail]>
[ Viresh: Updated Subject ]
Signed-off-by: Viresh Kumar <[e-mail]>

drivers/cpufreq/brcmstb-avs-cpufreq.c

···
 	int ret;
 
 	ret = cpufreq_unregister_driver(&brcm_avs_driver);
-	if (ret)
-		return ret;
+	WARN_ON(ret);
 
 	brcm_avs_prepare_uninit(pdev);