sparc: Add testsuite support
sparc: Add testsuite support

This commit provides the timestamp_serialize() define for the SPARC
architecture.

Co-authored-by: Nikolaus Huber <12f03d6109f02c677182aeaf7f7e06642ae76ab5@gmail.com>
Signed-off-by: Martin Åberg <37424e7fbe3f8590d57db5ed6ae5b8866742b6be@gaisler.com>

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