mips: Remove duplicate macro definitions

mips: Remove duplicate macro definitions

The INLINE_SYSCALL, INTERNAL_SYSCALL*, and internal_syscall* macros
are defined for MIPS in both libc/sysdeps/linux/mips/sysdep.h and
libc/sysdeps/linux/mips/bits/syscalls.h.  The macros are the same
in both cases except that syscalls.h defines internal_syscalls[567]
the same for N32 and N64 ABIs and has a different definition for O32.
I believe that is correct.  The sysdep.h header uses the O32 versions
for N32 and has different definitions for N64.  I think that is wrong
and that N32 and N64 should share the same definition (modulo the
type 'long' vs. 'long long' for the arguments.  This setup (from
sysdep.h) now agrees with what glibc has.

I am not positive about which header (sysdep.h vs syscalls.h) is
really the right one to have these definitions in but using sysdep.h
seems to work for all my builds.

Signed-off-by: Steve Ellcey <sellcey@mips.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>