arm64: define DMA_ERROR_CODE

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
CC: will.deacon@arm.com

Changes in v8:
- cast to dma_addr_t before returning.
Git-commit: 25b719d7b45947a79d298414cdfb5ec8fadf0ec8
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Ian Maund <imaund@codeaurora.org>