arm64: Move PCI_IOBASE closer to MODULES_VADDR

This is to reuse the same pmd table that is sparsely populated with
the modules space.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index d10778f..54f6116 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -114,7 +114,7 @@
  *  I/O port access primitives.
  */
 #define IO_SPACE_LIMIT		0xffff
-#define PCI_IOBASE		((void __iomem *)0xffffffbbfffe0000UL)
+#define PCI_IOBASE		((void __iomem *)(MODULES_VADDR - SZ_2M))
 
 static inline u8 inb(unsigned long addr)
 {