Revert "pinctrl: avoid unsafe code pattern in find_pinctrl()"

The commit breaks MMC enumeration on the Intel Merrifield
plaform.

Before:
[   36.439057] mmc0: SDHCI controller on PCI [0000:00:01.0] using ADMA
[   36.450924] mmc2: SDHCI controller on PCI [0000:00:01.3] using ADMA
[   36.459355] mmc1: SDHCI controller on PCI [0000:00:01.2] using ADMA
[   36.706399] mmc0: new DDR MMC card at address 0001
[   37.058972] mmc2: new ultra high speed DDR50 SDIO card at address 0001
[   37.278977] mmcblk0: mmc0:0001 H4G1d 3.64 GiB
[   37.297300]  mmcblk0: p1 p2 p3 p4 p5 p6 p7 p8 p9 p10

After:
[   36.436704] mmc2: SDHCI controller on PCI [0000:00:01.3] using ADMA
[   36.436720] mmc1: SDHCI controller on PCI [0000:00:01.0] using ADMA
[   36.463685] mmc0: SDHCI controller on PCI [0000:00:01.2] using ADMA
[   36.720627] mmc1: new DDR MMC card at address 0001
[   37.068181] mmc2: new ultra high speed DDR50 SDIO card at address 0001
[   37.279998] mmcblk1: mmc1:0001 H4G1d 3.64 GiB
[   37.302670]  mmcblk1: p1 p2 p3 p4 p5 p6 p7 p8 p9 p10

This reverts commit c153a4e.

Signed-off-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Linus Walleij <[email protected]>

Author: andy-shev

drivers/pinctrl/core.c

@@ -1022,20 +1022,17 @@ static int add_setting(struct pinctrl *p, struct pinctrl_dev *pctldev,
 
 static struct pinctrl *find_pinctrl(struct device *dev)
 {
-	struct pinctrl *entry, *p = NULL;
+	struct pinctrl *p;
 
 	mutex_lock(&pinctrl_list_mutex);
-
-	list_for_each_entry(entry, &pinctrl_list, node) {
-		if (entry->dev == dev) {
-			p = entry;
-			kref_get(&p->users);
-			break;
+	list_for_each_entry(p, &pinctrl_list, node)
+		if (p->dev == dev) {
+			mutex_unlock(&pinctrl_list_mutex);
+			return p;
 		}
-	}
 
 	mutex_unlock(&pinctrl_list_mutex);
-	return p;
+	return NULL;
 }
 
 static void pinctrl_free(struct pinctrl *p, bool inlist);
@@ -1143,6 +1140,7 @@ struct pinctrl *pinctrl_get(struct device *dev)
 	p = find_pinctrl(dev);
 	if (p) {
 		dev_dbg(dev, "obtain a copy of previously claimed pinctrl\n");
+		kref_get(&p->users);
 		return p;
 	}