Backport of this commit:

  commit b2167015043a458e9cf93b827b43eb5b7c552ce9
  Author: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
  Date:   Sat Nov 4 23:06:27 2017 +0100

    xkb: initialize tsyms

    This fixes some “Conditional jump depends on uninitialized value(s)”
    errors spotted by valgrind.
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>