PR1245 device lseek

[Joel Sherrill]

Hi,

This PR notes that device_lseek() always succeeds but
does nothing.  According to OpenGroup
http://www.opengroup.org/onlinepubs/000095399/functions/lseek.html,
lseek() should return ESPIPE for ttys, sockets, and pipes.

I may be having a brain freeze, but right now, I don't
see how to implement a seek on a block device like
a hard disk.  I know you have to be able to do it.

Any thoughts?

--joel