powerpc: Remove duplicated versionsort from libm.a (BZ 31789)

The powerpc32 have an extra versionsort provided by LFS
versionsort64.o.  It seems that 5226a81f
used the wrong check to create the alias for the LFS to non-LFS version.
It should not matter for _DIRENT_MATCHES_DIRENT64 since both symbols
have the same implementation.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>