x86, UML: 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>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/x86/um/asm/elf.h

@@ -210,7 +210,7 @@ extern int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu);
 
 #define ELF_EXEC_PAGESIZE 4096
 
-#define ELF_ET_DYN_BASE (2 * TASK_SIZE / 3)
+#define ELF_ET_DYN_BASE (TASK_SIZE / 3 * 2)
 
 extern long elf_aux_hwcap;
 #define ELF_HWCAP (elf_aux_hwcap)