Add touchpad of Dell XPS 13 9360 to Synaptics Intertouch list

Dear Linux folks,


On the Dell XPS 13 9360, Linux asks me to report the device DLL075b to 
be added to `forcepad_pnp_ids`.

[    7.180131] psmouse serio1: synaptics: Your touchpad (PNP: DLL075b PNP0f13) says it can support a different bus. If i2c-hid and hid-rmi are not used, you might want to try setting psmouse.synaptics_intertouch to 1 and report this to linux-input@vger.kernel.org.

I booted Linux 4.16-rc1 with `psmouse.synaptics_intertouch=1` added to 
the Linux command line, and everything continued to work.


Kind regards,

Paul