Solved
Bug: ADC with DMA, Init code not enabeling RCC_DMA_CLK on STM32L151
When creating ADC with DMA the call to MX_Adc_Init() is created before MX_DMA_Init() which in this case means that RCC clocks of DMA are not enabled during MX_ADC_Init(), which is odd. To fix this:
Init code should enable RCC_DMA clock in ADC_Init() or ensure correct init-order