avr32: fix integer overflow in ELF_ET_DYN_BASE

Almost all arches define ELF_ET_DYN_BASE as 2/3 of TASK_SIZE.
Though it seems that some architectures do this in a wrong way.
The problem is that 2*TASK_SIZE may overflow 32-bits so
the real ELF_ET_DYN_BASE becomes wrong.
Fix this overflow by dividing TASK_SIZE prior to multiplying:
	 (TASK_SIZE / 3 * 2)

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>

arch/avr32/include/asm/elf.h

@@ -84,7 +84,7 @@ typedef struct user_fpu_struct elf_fpregset_t;
    the loader.  We need to make sure that it is out of the way of the program
    that it will "exec", and that there is sufficient room for the brk.  */
 
-#define ELF_ET_DYN_BASE         (2 * TASK_SIZE / 3)
+#define ELF_ET_DYN_BASE         (TASK_SIZE / 3 * 2)
 
 
 /* This yields a mask that user programs can use to figure out what