[dev] [st] Fix the tab key

[Roberto E. Vargas Caballero]

Hello,

        After last patch serie tab key was not working correctly and this
patch fix the problem. I also want to comment this line in kmap:

        state &= ~Mod2Mask

I don't know why this line is writing there, but it removes any combination
using Super key. I think it is necessary remove this line.

Best regards,