ASoC: Rename soc_enum.max field with items

The name "max" in struct soc_enum is rather confusing since it
actually takes the number of items.  With "max", one might try to
assign (nitems - 1) value.

Rename the field to a more appropriate one, "items", which is also
used in struct snd_ctl_elem_info, too.

This patch also rewrites some code like "if (x > e->nitems - 1)" with
"if (x >= e->nitems)".  Not only the latter improves the readability,
it also fixes a potential bug when e->items is zero.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/codecs/wm8996.c

@@ -2595,7 +2595,7 @@ static void wm8996_retune_mobile_pdata(struct snd_soc_codec *codec)
 	dev_dbg(codec->dev, "Allocated %d unique ReTune Mobile names\n",
 		wm8996->num_retune_mobile_texts);
 
-	wm8996->retune_mobile_enum.max = wm8996->num_retune_mobile_texts;
+	wm8996->retune_mobile_enum.items = wm8996->num_retune_mobile_texts;
 	wm8996->retune_mobile_enum.texts = wm8996->retune_mobile_texts;
 
 	ret = snd_soc_add_codec_controls(codec, controls, ARRAY_SIZE(controls));