asm-generic: Fix typo in asm-generic/unistd.h.

>>From 9741f7928ef35416e49f329a64e623a109de5c2d Mon Sep 17 00:00:00 2001
From: Chen Liqin <liqin.chen@sunplusct.com>
Date: Mon, 26 Oct 2009 10:50:50 +0800
Subject: [PATCH] asm-generic: Fix typo in asm-generic/unistd.h.

Fixed __NR_ftruncate and __NR_ftruncate64 define in asm-generic/unistd.h.

Signed-off-by: Chen Liqin <liqin.chen@sunplusct.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>