mmc: sdhci: fix IS_ERR() checking of regulator_get()

There are two problems here:

The check for vmmc was printing an unnecessary pr_info() when
host->vmmc is NULL.

The intent of the check for vqmmc was to only remove UHS if we have a
regulator that doesn't support the required voltage, but since IS_ERR()
doesn't catch NULL, we were actually removing UHS modes if vqmmc isn't
present at all -- since it isn't present for most users, this breaks
UHS for them.  This patch fixes that UHS regression in 3.7-rc1.
Signed-off-by: Kevin Liu <kliu5@marvell.com>
Signed-off-by: Bin Wang <binw@marvell.com>
Reviewed-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/sdhci.c

@@ -2849,10 +2849,13 @@ int sdhci_add_host(struct sdhci_host *host)
 
 	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
 	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
-	if (IS_ERR(host->vqmmc)) {
-		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
+	if (IS_ERR_OR_NULL(host->vqmmc)) {
+		if (PTR_ERR(host->vqmmc) < 0) {
+			pr_info("%s: no vqmmc regulator found\n",
+				mmc_hostname(mmc));
 			host->vqmmc = NULL;
 		}
+	}
 	else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
 		regulator_enable(host->vqmmc);
 	else
@@ -2907,9 +2910,12 @@ int sdhci_add_host(struct sdhci_host *host)
 	ocr_avail = 0;
 
 	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
-	if (IS_ERR(host->vmmc)) {
-		pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc));
+	if (IS_ERR_OR_NULL(host->vmmc)) {
+		if (PTR_ERR(host->vmmc) < 0) {
+			pr_info("%s: no vmmc regulator found\n",
+				mmc_hostname(mmc));
 			host->vmmc = NULL;
+		}
 	} else
 		regulator_enable(host->vmmc);