drivers/net/cs89x0.c: Avoid using magic number in set_dma_mode
The constant DMA_RX_MODE is defined to be 0x14 in the local include file
cs89x0.h. Since a constant with the same name is used elsewhere with
set_dma_mode, it seems likely that this constant could be used here.
The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)