input/libinput: fix typo in set_middle_emulation
input/libinput: fix typo in set_middle_emulation

This fixes a typo in set_middle_emulation where it would set left
handed instead of middle emulation.

SirCmpwn/sway,1ace/sway,ascent12/sway,ascent12/sway,1ace/sway,ascent12/sway,1ace/sway