soc: qcom: subsystem_restart: Prevent kernel panic caused by modem crash

Just restart the modem if modem crash,
not worth making kernel panic.

This solves the problem of kernel panic
after modifying "Lock Bands" in the "Network Signal Guru" app.

Signed-off-by: Pzqqt <821026875@qq.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>