Add the dl_iterate_phdr function to libdl for arm.

Bug: 8410085
Change-Id: I94ed51bc5d4c626df7552c0e85c31ccee2d6568f

linker/linker.cpp

@@ -414,7 +414,7 @@ _Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr pc, int *pcount)
     return NULL;
 }
 
-#elif defined(ANDROID_X86_LINKER) || defined(ANDROID_MIPS_LINKER)
+#endif
 
 /* Here, we only have to provide a callback to iterate across all the
  * loaded libraries. gcc_eh does the rest. */
@@ -437,8 +437,6 @@ dl_iterate_phdr(int (*cb)(dl_phdr_info *info, size_t size, void *data),
     return rv;
 }
 
-#endif
-
 static Elf32_Sym* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name) {
     Elf32_Sym* symtab = si->symtab;
     const char* strtab = si->strtab;