m68knommu, net and DMA compile error

In the CONFIG_PCI=n case (the PCI code will be removed during this merge 
window) m68knommu does not set the Kconfig NO_DMA variable, but also 
does not provide the required functions, resulting in the following 
build error triggered by commit a40c24a13366e324bc0ff8c3bb107db89312c984
(net: Add SKB DMA mapping helper functions.):

<--  snip  -->

...
  LD      vmlinux
net/built-in.o: In function `skb_dma_unmap':
(.text+0xac5e): undefined reference to `dma_unmap_single'
net/built-in.o: In function `skb_dma_unmap':
(.text+0xac7a): undefined reference to `dma_unmap_page'
net/built-in.o: In function `skb_dma_map':
(.text+0xacdc): undefined reference to `dma_map_single'
net/built-in.o: In function `skb_dma_map':
(.text+0xace8): undefined reference to `dma_mapping_error'
net/built-in.o: In function `skb_dma_map':
(.text+0xad10): undefined reference to `dma_map_page'
net/built-in.o: In function `skb_dma_map':
(.text+0xad82): undefined reference to `dma_unmap_page'
net/built-in.o: In function `skb_dma_map':
(.text+0xadc6): undefined reference to `dma_unmap_single'
make[1]: *** [vmlinux] Error 1

<--  snip  -->


cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed