[MIPS] Fix 64-bit build for RM7000.

RM7000 has 40-bit virtual / 36-bit physical address space.
    
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

include/asm-mips/addrspace.h

@@ -129,6 +129,7 @@
 #if defined (CONFIG_CPU_R4300)						\
     || defined (CONFIG_CPU_R4X00)					\
     || defined (CONFIG_CPU_R5000)					\
+    || defined (CONFIG_CPU_RM7000)					\
     || defined (CONFIG_CPU_NEVADA)					\
     || defined (CONFIG_CPU_TX49XX)					\
     || defined (CONFIG_CPU_MIPS64)