ld.so: Remove __libc_memalign

It is no longer needed since commit 6c444ad6e9
(elf: Do not use memalign for TCB/TLS blocks allocation [BZ #17730]).
Applications do not link against ld.so and will use the definition in
libc.so, so there is no ABI impact.

sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data

@@ -18,10 +18,8 @@ libc.so: malloc
 libc.so: memalign
 libc.so: realloc
 libm.so: matherr
-# The dynamic loader uses __libc_memalign internally to allocate
-# aligned TLS storage. The other malloc family of functions are
-# expected to allow user symbol interposition.
-ld.so: __libc_memalign
+# The main malloc is interposed into the dynamic linker, for
+# allocations after the initial link (when dlopen is used).
 ld.so: malloc
 ld.so: calloc
 ld.so: realloc