openrisc: remove bogus nops and shutdowns

Nop 42 is some leftover debugging thing by the looks of it. Nop 1 will
shut down the simulator, which isn't what we want, since it makes it
impossible to handle errors.

Cc: Stafford Horne <shorne@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>