[ESan] [MIPS] Fix workingset-signal-posix.cpp on MIPS

Used uptr for __sanitizer_kernel_sigset_t.sig to avoid byte order issues on big endian systems

Reviewd by bruening.
Differential: D24332 

llvm-svn: 283438

compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h

@@ -607,7 +607,7 @@ namespace __sanitizer {
   typedef __sanitizer_sigset_t __sanitizer_kernel_sigset_t;
 #elif defined(__mips__)
   struct __sanitizer_kernel_sigset_t {
-    u8 sig[16];
+    uptr sig[2];
   };
 #else
   struct __sanitizer_kernel_sigset_t {