sandbox: move a function prototype

Since host_get_dev_errr() is defined in drivers/block/sandbox.c,
the associated function prototype should be in a more appropriate
header file.

Fixes: commit 4101f6879256 ("dm: Drop the block_dev_desc_t typedef")
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
2 files changed