Revert "drivers: of: add initialization code for dma reserved memory"

This reverts commit 9d8eab7a. There is
still no consensus on the bindings for the reserved memory and various
drawbacks of the proposed solution has been shown, so the best now is to
revert it completely and start again from scratch later.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>