drivers: CAN: Fix unused parameter warnings when compiling with -Wextra
drivers: CAN: Fix unused parameter warnings when compiling with -Wextra

Since the CAN header file is included directly by application code,
an application developer including this file and only applying
-Wextra to the application source files will see many warnings.

Signed-off-by: Pete Dietl <601107ffea705e2a2d49847fb81708f699ff5257@gmail.com>

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