WIP: Added new device: Sony Xperia J

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WilliamO7 or anyone else: if you have updated the code for another review, please open up a new merge request. Sorry for the trouble.

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Created by: WilliamO7

So this is the second device I've ported, and boy was this one difficult!

• Two new packages were added, unpackelf and mkelf to deal with the non-standard boot images the phone uses (don't ask me why, blame Sony.)
• Therefore, pmb and the mkinitfs programs were modified to accomodate this.
• Info will go up into the wiki soon(tm) - need to do other stuff first.

Device status: Convinced the phone does not boot at all. I cannot get a usb shell and the screen stays turned off.

EDIT: It does boot using the original kernel in the boot.img here with the generated initramfs (no screen still however).