dma:coherent: manage resizable memory with single device

This is necessary to avoid unusable memory between device nodes.

Bug 1517584

Change-Id: I37ac104fa5e512758a4df299424fa0456f368bb6
Signed-off-by: Krishna Reddy <[email protected]>
Reviewed-on: http://git-master/r/486855
GVS: Gerrit_Virtual_Submit
Reviewed-by: Prajakta Gudadhe <[email protected]>
Reviewed-by: Sri Krishna Chowdary <[email protected]>
Reviewed-by: Mandar Padmawar <[email protected]>
Tested-by: Mandar Padmawar <[email protected]>