ART: Allow to compile interpret-only mips64 files

Include enough infrastructure to allow cross-compiling for mips64,
interpret-only. This includes the instruction-set-features, frame
size info and utils assembler.

Also add a disassembler for oatdump, and support in patchoat.

Note: the runtime cannot run mips64, yet.

Change-Id: Id106581fa76b478984741c62a8a03be0f370d992
diff --git a/runtime/elf_utils.h b/runtime/elf_utils.h
index 3579e27..418d937 100644
--- a/runtime/elf_utils.h
+++ b/runtime/elf_utils.h
@@ -31,6 +31,7 @@
 #define EF_MIPS_ABI_O32 0x00001000
 #define EF_MIPS_ARCH_32R2 0x70000000
 #define EF_MIPS_ARCH_32R6 0x90000000
+#define EF_MIPS_ARCH_64R6 0xa0000000
 
 #define EI_ABIVERSION 8
 #define EM_ARM 40