ARM: Orion: Remove redundant init_dma_coherent_pool_size()

The patch:

  387870f2

 mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls

makes these calls on Kirkwood and Orion5x redundant. The drivers are
not making atomic requests for coherent memory and hence the default
pool size is now sufficient.

Jason Cooper added mach-mvebu/ hunk, and corrected minor typos in commit
message.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>