r600g/sb: Don't read junk after EOP

r600g/sb: Don't read junk after EOP

Shaders that contain instruction data after an instruction with EOP could end
up parsing that as an instruction, leading to various crashes and asserts in
SB as it gets very confused if it sees for instance a loop start instruction
jumping off to some random point.

Add a couple of asserts, and print EOP bit if set in old asm printer.

Signed-off-by: Glenn Kennard <glenn.kennard@gmail.com>
Cc: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>