boards: intel_s1000_crb: add zephyr,flash-controller to DTS
boards: intel_s1000_crb: add zephyr,flash-controller to DTS

The board has a SPI NOR flash enabled by default but was missing
the "zephyr,flash-controller" in DTS. This prevents the flash
shell sample to compile. So add the DTS entry.

Fixes #26764

Signed-off-by: Daniel Leung <d94e04d205b5962d7873a139ef298b03c1717f72@intel.com>

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