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/board/ppmc7xx/pci.c b/board/ppmc7xx/pci.c
index bf133b7..2948531 100644
--- a/board/ppmc7xx/pci.c
+++ b/board/ppmc7xx/pci.c
@@ -45,7 +45,7 @@
 	CONFIG_SYS_PCI_MEMORY_BUS,
 	CONFIG_SYS_PCI_MEMORY_PHYS,
 	CONFIG_SYS_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,