samples/drivers/spi_flash: fix sample regex
samples/drivers/spi_flash: fix sample regex

The sample.yml regex did not match the implementation anymore.

Signed-off-by: Christian Taedcke <5dfb12f5b8690cb9c18e955016e7e3173b81d0d8@lemonbeat.com>

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