sh: Add in some ptrace definitions from GDB.

Plugs in PT_TEXT_END_ADDR/PT_TEXT_ADDR/PT_DATA_ADDR/PT_TEXT_LEN
definitions.

Signed-off-by: Kieran Bingham <kieranbingham@gmail.com>
Signed-off-by: Peter Griffin <pgriffin@mpc-data.co.uk>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>