ALSA: pcm: Use krealloc() for resizing the rules array

Just a minor simplification.  Change from kcalloc() shouldn't matter
as each array element is fully initialized.

Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/pcm_lib.c

@@ -1129,16 +1129,12 @@ int snd_pcm_hw_rule_add(struct snd_pcm_runtime *runtime, unsigned int cond,
 	if (constrs->rules_num >= constrs->rules_all) {
 		struct snd_pcm_hw_rule *new;
 		unsigned int new_rules = constrs->rules_all + 16;
-		new = kcalloc(new_rules, sizeof(*c), GFP_KERNEL);
+		new = krealloc(constrs->rules, new_rules * sizeof(*c),
+			       GFP_KERNEL);
 		if (!new) {
 			va_end(args);
 			return -ENOMEM;
 		}
-		if (constrs->rules) {
-			memcpy(new, constrs->rules,
-			       constrs->rules_num * sizeof(*c));
-			kfree(constrs->rules);
-		}
 		constrs->rules = new;
 		constrs->rules_all = new_rules;
 	}