au1100fb: remove a bogus dma_free_nonconsistent call

au1100fb is using managed dma allocations, so it doesn't need to
explicitly free the dma memory in the error path (and if it did
it would have to use the managed version).

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>