modem: hl7800: ensure IP family set correctly
modem: hl7800: ensure IP family set correctly

Ensure that the IP family is synchronized between the PDP
context and the GPRS connection.
There were cases where they could get out of sync.

Signed-off-by: Ryan Erickson <445db09b136432317bdbb8e4308a30651390c2e2@lairdconnect.com>

finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr