net: usb: qmi_wwan: add Compal EXM-G1x support

The Compal EXM-G1x is a Qualcomm SDX12-based LTE modem. Add support for
its QMI WWAN interface 8 using the DTR quirk.

Tested on a Compal EXM-G1x modem.

Signed-off-by: Ian Lin <jisayme@gmail.com>
Link: https://patch.msgid.link/20260831084124.65074-1-jisayme@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>