alpha, cris, mips, ppc, sh, sparc: fix decoding of sigsuspend syscall

alpha, cris, mips, ppc, sh, sparc: fix decoding of sigsuspend syscall

On some architectures old sigsuspend syscall takes the signal mask from
the 3rd argument, on some from the 1st.  And, if it wasn't peculiar
enough, the signal mask is passed by value on all architectures except
mips where it's passed by reference.

* signal.c (SYS_FUNC(sigsuspend)): Take the signal mask from the last
argument.
* linux/alpha/syscallent.h (sigsuspend): Set nargs to 1.
* linux/crisv10/syscallent.h: Likewise.
* linux/mips/syscallent-o32.h: Likewise.
* linux/powerpc/syscallent.h: Likewise.
* linux/powerpc64/syscallent.h: Likewise.
* linux/sh/syscallent.h: Likewise.
* linux/sh64/syscallent.h: Likewise.
* linux/sparc/syscallent.h: Likewise.
* linux/sparc64/syscallent.h: Likewise.
* tests/sigsuspend.c: New file.
* tests/gen_tests.in (sigsuspend): New entry.
* tests/pure_executables.list: Add sigsuspend.
* tests/.gitignore: Likewise.
* NEWS: Mention this fix.