Getting null pointer dereferencing crash while rebooting or shutting
down the caracalla gateway.
This is because the device operating mode selection is done from
/etc/modprobe.d/rs9113.conf. Initially it is (13 - WiFi + BT),
all WiFi and BT related structures are initialized, but if the
operating mode is (8 - BT LE alone), WiFi related structures are not
been initialized, dereferencing the NULL structures in the
rsi_shutdown function causing this issue.
Handled it by putting proper null checks.