Remove duplicated definitions of size_t and ssize_t

See 3975cec694a0c9b42e3f7e671fcd678da92836c3

Change-Id: Ia40ff8de3ffe923fb983bb116b740942724c641a

ndk/platforms/android-3/include/sys/types.h

@@ -85,12 +85,6 @@ typedef  .... pthread_rwlock_attr_t;
 typedef  .... pthread_t;
 #endif
 
-#ifndef _SIZE_T_DEFINED_
-#define _SIZE_T_DEFINED_
-typedef unsigned int  size_t;
-#endif
-
-/* size_t is defined by the GCC-specific <stddef.h> */
 #ifndef _SSIZE_T_DEFINED_
 #define _SSIZE_T_DEFINED_
 typedef long int  ssize_t;