PCI MSI: Define PCI_MSI_MASK_32/64

Impact: cleanup, improve readability

Define PCI_MSI_MASK_32/64 for 32/64bit devices, instead of using
implicit offset (-4), "PCI_MSI_MASK_BIT - 4" and "PCI_MSI_MASK_BIT".

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Reviewed-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index dcba766..83b02f5 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -295,8 +295,9 @@
 #define PCI_MSI_ADDRESS_LO	4	/* Lower 32 bits */
 #define PCI_MSI_ADDRESS_HI	8	/* Upper 32 bits (if PCI_MSI_FLAGS_64BIT set) */
 #define PCI_MSI_DATA_32		8	/* 16 bits of data for 32-bit devices */
+#define PCI_MSI_MASK_32		12	/* Mask bits register for 32-bit devices */
 #define PCI_MSI_DATA_64		12	/* 16 bits of data for 64-bit devices */
-#define PCI_MSI_MASK_BIT	16	/* Mask bits register */
+#define PCI_MSI_MASK_64		16	/* Mask bits register for 64-bit devices */
 
 /* MSI-X registers (these are at offset PCI_MSIX_FLAGS) */
 #define PCI_MSIX_FLAGS		2