soc: atmel: sam: Add invalidate d-cache at z_arm_platform_init

Before that fix, the SOC was unable to boot properly.
Starting turned directly into z_arm_usage_fault().
Fixes zephyrproject-rtos#73485

Signed-off-by: Sven Ginka <sven.ginka@gmail.com>
(cherry picked from commit c3d7b1c9)