MIPS: Add NUMA support for Loongson-3

Multiple Loongson-3A chips can be interconnected with HT0-bus. This is
a CC-NUMA system that every chip (node) has its own local memory and
cache coherency is maintained by hardware. The 64-bit physical memory
address format is as follows:

0x-0000-YZZZ-ZZZZ-ZZZZ

The high 16 bits should be 0, which means the real physical address
supported by Loongson-3 is 48-bit. The "Y" bits is the base address of
each node, which can be also considered as the node-id. The "Z" bits is
the address offset within a node, which means every node has a 44 bits
address space.

Macros XPHYSADDR and MAX_PHYSMEM_BITS are modified unconditionally,
because many other MIPS CPUs have also extended their address spaces.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/7187/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/addrspace.h b/arch/mips/include/asm/addrspace.h
index 3f74545..3b0e51d 100644
--- a/arch/mips/include/asm/addrspace.h
+++ b/arch/mips/include/asm/addrspace.h
@@ -52,7 +52,7 @@
  */
 #define CPHYSADDR(a)		((_ACAST32_(a)) & 0x1fffffff)
 #define XPHYSADDR(a)		((_ACAST64_(a)) &			\
-				 _CONST64_(0x000000ffffffffff))
+				 _CONST64_(0x0000ffffffffffff))
 
 #ifdef CONFIG_64BIT