sh: remove nargs from __SYSCALL

sh: remove nargs from __SYSCALL

The __SYSCALL macro's arguments are system call number, system call
entry name and number of arguments for the system call.

Argument- nargs in __SYSCALL(nr, entry, nargs) is neither calculated nor
used anywhere.  So it would be better to keep the implementation as
__SYSCALL(nr, entry).  This unifies the implementation with some other
architectures too.

Link: http://lkml.kernel.org/r/1546443445-21075-2-git-send-email-firoz.khan@linaro.org
Signed-off-by: Firoz Khan <firoz.khan@linaro.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Simon Horman <horms+renesas@verge.net.au>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>