pci: Rename PCI_REGION_MEMORY to PCI_REGION_SYS_MEMORY for clarity

The PCI_REGION_MEMORY and PCI_REGION_MEM are a bit to similar and
can be confusing when reading the code.

Rename PCI_REGION_MEMORY to PCI_REGION_SYS_MEMORY to clarify its used
for system memory mapping purposes.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/cpu/i386/sc520.c b/cpu/i386/sc520.c
index 12e8f38..b958f8d 100644
--- a/cpu/i386/sc520.c
+++ b/cpu/i386/sc520.c
@@ -341,7 +341,7 @@
 		       SC520_PCI_MEMORY_BUS,
 		       SC520_PCI_MEMORY_PHYS,
 		       SC520_PCI_MEMORY_SIZE,
-		       PCI_REGION_MEM | PCI_REGION_MEMORY);
+		       PCI_REGION_MEM | PCI_REGION_SYS_MEMORY);
 
 	/* PCI memory space */
 	pci_set_region(hose->regions + 1,