hwstub/tools/shell: add JZ4760B and Fiio X1 code

The jz code can do several useful things like dumping the IPL and SPL.
The Fiio code can play with backlight and has code do dump the IPL
and SPL with the correct parameters (extracted by reverse engineering).

Change-Id: I317b3174f5db8d38c9a56670c1d45565142ec208
5 files changed