mmc: sdhci-pci: Fix possibility of chip->fixes being null

It is possible for chip->fixes to be null.  Check before dereferencing it.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable <stable@vger.kernel.org> # 3.11+
Signed-off-by: Chris Ball <chris@printf.net>

drivers/mmc/host/sdhci-pci.c

@@ -1378,7 +1378,8 @@ static struct sdhci_pci_slot *sdhci_pci_probe_slot(
 	 * from runtime suspend.  If it is not there, don't allow runtime PM.
 	 * Note sdhci_pci_add_own_cd() sets slot->cd_gpio to -EINVAL on failure.
 	 */
-	if (chip->fixes->own_cd_for_runtime_pm && !gpio_is_valid(slot->cd_gpio))
+	if (chip->fixes && chip->fixes->own_cd_for_runtime_pm &&
+	    !gpio_is_valid(slot->cd_gpio))
 		chip->allow_runtime_pm = false;
 
 	return slot;