[PATCH] xtensa: fix system call interface

This is a long outstanding patch to finally fix the syscall interface.  The
constants used for the system calls are those we have provided in our libc
patches.  This patch also fixes the shmbuf and stat structure, and fcntl
definitions.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>