From: Andi Kleen <ak@suse.de>

sys_sendfile has a hardcoded 2GB limit.  64bit architectures should
probably always use sys_sendfile64() in their native system tables, because
for them sizeof(off_t) == sizeof(loff_t).  This patch does this.  It seemed
easier to just change the 64bit entry tables instead of fixing up all the
emulation layers to do 2GB checks on their own.

I changed all 64bit architectures except for parisc64, which seemed to
already have a sendfile64.