drivers: uart_mux: Fix compilation after logging changes
drivers: uart_mux: Fix compilation after logging changes

The logging macros use _Generic() atm and it started to complain
when we are trying to print pointer value of gsm_dlci and gsm_mux
structs. Cast the pointer value to (void *) to overcome this.

Fixes #35329

Signed-off-by: Jukka Rissanen <f9f077d1da4c7aa947f9864fa5a28c3588f6a45d@linux.intel.com>

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