sim_core: add ldi, trace and labeling corrections.

in moving the majority of instructions to follow use of register
 macros, ldi was missed.

get_h4_k16() was incorrectly labeled where get_h4_k8() was intended
 as k is an 8 bit quantity not 16.

get_o_12() was changed to get_o12() following the convention set
 forth with the other macros.

several trace statements were missed during the conversion and fixed.

ORI was incorrecly labeled as ANDI in the description and corrected.

	modified:   sim/sim_core.c