ARM: 8699/1: dma-mapping: Remove init_dma_coherent_pool_size()

There are no users of init_dma_coherent_pool_size() left due to
387870f2 ("mm: dmapool: use provided gfp flags for all
dma_alloc_coherent() calls"), so remove it.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>