Replace the long ago deprecated and now no longer supported
"-usbdevice tablet" option with the newer "-device usb-tablet"
in the QB_OPT_APPEND definition in our local x86_64 tuning file.
Without this, runqemu fails for the qemux86-64 target on dunfell.
Bug-AGL: SPEC-3302
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: I46fcbc615821e7ac54a913ca08b66abf2abaaa0b