PCI / PM: Enforce type casting for pci_power_t

When casting variables of type pci_power_t, a static analysis tool complains:

  include/linux/pci.h:119:37: warning: cast from restricted pci_power_t

Enforce type casting to make the static analyzer happy.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

include/linux/pci.h

@@ -116,7 +116,7 @@ extern const char *pci_power_names[];
 
 static inline const char *pci_power_name(pci_power_t state)
 {
-	return pci_power_names[1 + (int) state];
+	return pci_power_names[1 + (__force int) state];
 }
 
 #define PCI_PM_D2_DELAY		200