nptl: Consolidate sem_init implementations

Current sparc32 sem_init and default one only differ on sem.newsem.pad
initialization.  This patch removes sparc32 and sparc32v9 sem_init arch
specific implementation and set sparc32 to use nptl default one.
The default implementation sets the required sem.newsem.pad to 0 (which
is ununsed in other architectures).

I checked on i686 and a sparc32v9 build.

        * nptl/sem_init.c (sem_init): Init pad value to 0.
        * sysdeps/sparc/sparc32/sem_init.c: Remove file.
        * sysdeps/sparc/sparc32/sparcv9/sem_init.c: Likewise.