[PATCH] csky: fixups after bootmem removal

[Mike Rapoport]

Hi,

The below patch fixes the bootmem leftovers in csky. It is based on the
current mmots and csky build there fails because of undefined reference to
dma_direct_ops:

  MODPOST vmlinux.o
kernel/dma/mapping.o: In function `dmam_alloc_attrs':
kernel/dma/mapping.c:143: undefined reference to `dma_direct_ops'
kernel/dma/mapping.o: In function `dmam_declare_coherent_memory':
kernel/dma/mapping.c:184: undefined reference to `dma_direct_ops'
mm/dmapool.o: In function `dma_free_attrs': 
include/linux/dma-mapping.h:558: undefined reference to `dma_direct_ops'

I've blindly added "select DMA_DIRECT_OPS" to arch/csky/Kconfig and it
fixed the build, but I really have no idea if this the right thing to do...