printk: nbcon: Use raw_cpu_ptr() instead of open coding

There is no need to open code a non-migration-checking
this_cpu_ptr(). That is exactly what raw_cpu_ptr() is.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/87plpum4jw.fsf@jogness.linutronix.deSigned-off-by: Petr Mladek <pmladek@suse.com>

kernel/printk/nbcon.c

@@ -998,8 +998,7 @@ static __ref unsigned int *nbcon_get_cpu_emergency_nesting(void)
 	if (!printk_percpu_data_ready())
 		return &early_nbcon_pcpu_emergency_nesting;
 
-	/* Open code this_cpu_ptr() without checking migration. */
-	return per_cpu_ptr(&nbcon_pcpu_emergency_nesting, raw_smp_processor_id());
+	return raw_cpu_ptr(&nbcon_pcpu_emergency_nesting);
 }
 
 /**