x86/PCI: Describe @reg for type1_access_ok()

Describe missed parameter in documentation of type1_access_ok().
Otherwise "make W=1 arch/x86/pci/" produces the following warning:
  CHECK   arch/x86/pci/intel_mid_pci.c
  CC      arch/x86/pci/intel_mid_pci.o
  arch/x86/pci/intel_mid_pci.c:152: warning: Function parameter or member 'reg' not described in 'type1_access_ok'
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

arch/x86/pci/intel_mid_pci.c

@@ -142,6 +142,7 @@ static int pci_device_update_fixed(struct pci_bus *bus, unsigned int devfn,
  * type1_access_ok - check whether to use type 1
  * @bus: bus number
  * @devfn: device & function in question
+ * @reg: configuration register offset
  *
  * If the bus is on a Lincroft chip and it exists, or is not on a Lincroft at
  * all, the we can go ahead with any reads & writes.  If it's on a Lincroft,