drivers: dma-removed: introduce no-map-fixup

For some use cases, it is not known beforehand, how much
removed (carve-out) region size must be reserved. Hence
the reserved region size might need to be adjusted to
support varying use cases. In such cases maintaining
different device tree configurations to support varying
carve-out region size is difficult.

Introduce an optional device tree property, to
reserved-memory, "no-map-fixup" which works in tandem with
"removed-dma-pool" compatibility that tries to shrink and
adjust the removed area on very first successful allocation.
At end of which it returns the additional (unused) pages
from the region back to the system.

Point to note is this that this adjustment is done on very
first allocation and thereafter the region size is big
enough only to support maximum of first allocation request
size. This fixup is attempted only once upon first
allocation and never after that. Clients can allocate and
free from this region as any other dma region.

As the description suggests this type of region is specific
to certain special needs and is not to be used for common
use cases.

Change-Id: I31f49d6bd957814bc2ef3a94910425b820ccc739
Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>