Kobo: Fix the input translation on the Elipsa 2E

[NiLuJe]

Apparently it mirrors on the Y axis. Or the panel vs. touch rotations are wonkier than expected or ...something.

Brain hurty >_<".

Followup to #10719

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This change is 

[NiLuJe]

Apparently it mirrors on the Y axis

I'd need to check another Elan device tomorrow, but the DTB (... at least the one in the kernel sources, that may not actually match the release, as usual ;p) for the board (EA0T00) sets revert_y_flag = <0>;, and the driver (drivers/input/touchscreen/elants_i2c.c) sets revert_y_flag = !revert_y_flag; on 16Bits_mirror boards (NTXHWConfig DisplayBusWidth (35) is 3, which is in fact the case for that board), so, that would seem to track.

EDIT: Or not. That bit of code is behind a sunxi ifdef.

EDIT²: Then again, that same DTB also sets exchange_x_y_flag to 0, so we might be back to "it's not the right dtb" or... something.

TL;DR: I'm going to go with "fuck it", if it just happens to work, regardless of why ;p.

[Frenzie]

lol