Remove socket.S implementation

Remove socket.S implementation

This patch removes the socket.S implementation for all ports and replace
it by a C implementation using socketcall.  For ports that implement
the syscall directly, there is no change.

The patch idea is to simplify the socket function implementation that
uses the socketcall to be based on C implemetation instead of a pseudo
assembly implementation with arch specific parts.  The patch then remove
the assembly implementatation for the ports which uses socketcall
(i386, microblaze, mips, powerpc, sparc, m68k, s390 and sh).

I have cross-build GLIBC for afore-mentioned ports and tested on both
i386 and ppc32 without regressions.