Pull up following revision(s) (requested by rin in ticket #1175):

sys/arch/aarch64/aarch64/trap.c: revision 1.28,1.31,1.32 (patch)

- add support conditionally execution for A32 instruction emulation
- separated the processing of ARM and THUMB emul clearly. do not confuse the Thumb-32bit instruction with the ARM instruction.
- use far_el1 instead of tf_pc to return correct fault address when instruction emulation

(martin)