qcom modem kick start

Here is a small howto about kick start modem

Ref to: https://gitlab.com/msm8998-mainline/linux/-/issues/15

1. Add needed nodes to devicetree,
2. prepare modem.mbn
3. put the modem.mbn into boot ramdisk
4. boot with new ramdisk/device-tree
5. kick start with echo start > /sys/devices/platform/soc/4080000.remoteproc/remoteproc/remoteproc0/state

ATM there are some issue happened and caused modem to hang.

More to come.