mx6ul_14x14_evk: Remove CONFIG_FEC_DMA_MINALIGN

CONFIG_FEC_DMA_MINALIGN is not used anywhere, so let's remove it.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Reviewed-by: Peng Fan <Peng.Fan@freescale.com>