mmc: pwrseq_simple: Make reset-gpios optional to match doc

The DT binding doc says reset-gpios is an optional property but the code
currently bails out if it is omitted.

This is a regression since it breaks previously working device trees.
Fix it by restoring the original documented behaviour.

Fixes: ce037275861e ("mmc: pwrseq_simple: use GPIO descriptors array API")
Tested-by: Tony Lindgren <[e-mail]>
Signed-off-by: Martin Fuzzey <[e-mail]>
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/core/pwrseq_simple.c

···
 static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
 					      int value)
 {
-	int i;
 	struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
-	int values[reset_gpios->ndescs];
 
-	for (i = 0; i < reset_gpios->ndescs; i++)
-		values[i] = value;
+	if (!IS_ERR(reset_gpios)) {
+		int i;
+		int values[reset_gpios->ndescs];
 
-	gpiod_set_array_value_cansleep(reset_gpios->ndescs, reset_gpios->desc,
-				       values);
+		for (i = 0; i < reset_gpios->ndescs; i++)
+			values[i] = value;
+
+		gpiod_set_array_value_cansleep(
+			reset_gpios->ndescs, reset_gpios->desc, values);
+	}
 }
 
 static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
···
 	struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
 					struct mmc_pwrseq_simple, pwrseq);
 
-	gpiod_put_array(pwrseq->reset_gpios);
+	if (!IS_ERR(pwrseq->reset_gpios))
+		gpiod_put_array(pwrseq->reset_gpios);
 
 	if (!IS_ERR(pwrseq->ext_clk))
 		clk_put(pwrseq->ext_clk);
···
 	}
 
 	pwrseq->reset_gpios = gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
-	if (IS_ERR(pwrseq->reset_gpios)) {
+	if (IS_ERR(pwrseq->reset_gpios) &&
+	    PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
+	    PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
 		ret = PTR_ERR(pwrseq->reset_gpios);
 		goto clk_put;
 	}