x86: vSMP: Fix is_vsmp_box()

is_vsmp_box() currently does not work on vSMPowered systems,  as pci cfg
space is not read correctly -- This patch fixes it.
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/vsmp_64.c

@@ -84,8 +84,10 @@ int is_vsmp_box(void)
 		return vsmp;
 
 	/* Check if we are running on a ScaleMP vSMP box */
-	if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
-	     (PCI_VENDOR_ID_SCALEMP || (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
+	if ((read_pci_config_16(0, 0x1f, 0, PCI_VENDOR_ID) ==
+	     PCI_VENDOR_ID_SCALEMP) &&
+	    (read_pci_config_16(0, 0x1f, 0, PCI_DEVICE_ID) ==
+	    PCI_DEVICE_ID_SCALEMP_VSMP_CTL))
 		vsmp = 1;
 
 	return vsmp;