scsi: ufs: ufs-pci: Correct check for RESET DSM

dsm_fns is a bitmap, and it is 0-indexed according to the check in
__intel_dsm function. But common initialization was checking it as if it
was 1-indexed. This patch corrects the discrepancy. This change won't break
any existing calls to the function, since before the change both bits 0 and
1 were checked and needed to be set.

Link: https://lore.kernel.org/r/20220728111748.v3.1.I22460c4f4a9ccf2c96c3f9bb392b409926d80b2f@changeid
Reviewed-by: Adrian Hunter <[e-mail]>
Signed-off-by: Daniil Lunev <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/ufs/host/ufshcd-pci.c

···
 	void (*late_init)(struct ufs_hba *hba);
 };
 
-enum {
+enum intel_ufs_dsm_func_id {
 	INTEL_DSM_FNS		=  0,
 	INTEL_DSM_RESET		=  1,
 };
···
 static const guid_t intel_dsm_guid =
 	GUID_INIT(0x1A4832A0, 0x7D03, 0x43CA,
 		  0xB0, 0x20, 0xF6, 0xDC, 0xD1, 0x2A, 0x19, 0x50);
+
+static bool __intel_dsm_supported(struct intel_host *host,
+				  enum intel_ufs_dsm_func_id fn)
+{
+	return fn < 32 && fn >= 0 && (host->dsm_fns & (1u << fn));
+}
+
+#define INTEL_DSM_SUPPORTED(host, name) \
+	__intel_dsm_supported(host, INTEL_DSM_##name)
 
 static int __intel_dsm(struct intel_host *intel_host, struct device *dev,
 		       unsigned int fn, u32 *result)
···
 static int intel_dsm(struct intel_host *intel_host, struct device *dev,
 		     unsigned int fn, u32 *result)
 {
-	if (fn > 31 || !(intel_host->dsm_fns & (1 << fn)))
+	if (!__intel_dsm_supported(intel_host, fn))
 		return -EOPNOTSUPP;
 
 	return __intel_dsm(intel_host, dev, fn, result);
···
 {
 	struct intel_host *host = ufshcd_get_variant(hba);
 
-	if (host->dsm_fns & INTEL_DSM_RESET) {
+	if (INTEL_DSM_SUPPORTED(host, RESET)) {
 		u32 result = 0;
 		int err;
 
···
 		return -ENOMEM;
 	ufshcd_set_variant(hba, host);
 	intel_dsm_init(host, hba->dev);
-	if (host->dsm_fns & INTEL_DSM_RESET) {
+	if (INTEL_DSM_SUPPORTED(host, RESET)) {
 		if (hba->vops->device_reset)
 			hba->caps |= UFSHCD_CAP_DEEPSLEEP;
 	} else {