Merged in raiden00/nuttx (pull request #520)

Master

* stm32: add ADC DMA support to STM32F33 configuration

* stm32f33xxx_adc.c: fix compilation if no DMA

* nucleo-f334r8: eliminate warning

* nucleo-f334r8: add highpri example configuration

Approved-by: Gregory Nutt <gnutt@nuttx.org>