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/drivers/pci/msi.h b/drivers/pci/msi.h
index 4fed592..a066284 100644
--- a/drivers/pci/msi.h
+++ b/drivers/pci/msi.h
@@ -16,9 +16,9 @@
 #define msi_lower_address_reg(base)	(base + PCI_MSI_ADDRESS_LO)
 #define msi_upper_address_reg(base)	(base + PCI_MSI_ADDRESS_HI)
 #define msi_data_reg(base, is64bit)	\
-	( (is64bit == 1) ? base+PCI_MSI_DATA_64 : base+PCI_MSI_DATA_32 )
-#define msi_mask_bits_reg(base, is64bit) \
-	( (is64bit == 1) ? base+PCI_MSI_MASK_BIT : base+PCI_MSI_MASK_BIT-4)
+	(base + ((is64bit == 1) ? PCI_MSI_DATA_64 : PCI_MSI_DATA_32))
+#define msi_mask_reg(base, is64bit)	\
+	(base + ((is64bit == 1) ? PCI_MSI_MASK_64 : PCI_MSI_MASK_32))
 #define is_64bit_address(control)	(!!(control & PCI_MSI_FLAGS_64BIT))
 #define is_mask_bit_support(control)	(!!(control & PCI_MSI_FLAGS_MASKBIT))