doc: boards: v2m_beetle: fix conversion to cmake
doc: boards: v2m_beetle: fix conversion to cmake

This board doesn't support the 'flash' goal, which was mistakenly
included during the CMake conversion.

Signed-off-by: Marti Bolivar <fd5da480b758a78208111e6ae5c6806e1f887137@opensourcefoundries.com>

ldts/zephyr,punitvara/zephyr,nashif/zephyr,explora26/zephyr,mbolivar/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,Vudentz/zephyr,aceofall/zephyr-iotos,kraj/zephyr,punitvara/zephyr,Vudentz/zephyr,nashif/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,explora26/zephyr,finikorg/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,explora26/zephyr,aceofall/zephyr-iotos,mbolivar/zephyr,GiulianoFranchetto/zephyr,aceofall/zephyr-iotos,Vudentz/zephyr,punitvara/zephyr,galak/zephyr,kraj/zephyr,galak/zephyr,Vudentz/zephyr,kraj/zephyr,kraj/zephyr,mbolivar/zephyr,GiulianoFranchetto/zephyr,zephyriot/zephyr,mbolivar/zephyr,ldts/zephyr,ldts/zephyr,aceofall/zephyr-iotos,finikorg/zephyr,zephyriot/zephyr,finikorg/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,kraj/zephyr,aceofall/zephyr-iotos,zephyriot/zephyr,galak/zephyr,Vudentz/zephyr,zephyriot/zephyr,punitvara/zephyr,galak/zephyr,nashif/zephyr,nashif/zephyr,mbolivar/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,zephyriot/zephyr