Input: I8042 - add Acer Aspire 7738 to the nomux list

When KBC is in active multiplexing mode the touchpad on this laptop does
not work.

Reported-by: Bilal Koc <koc.bilo@googlemail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>