Retain RGB1 iommu information during base layer swap so that iommu used by RGB1 can be freed back to pool later. Change-Id: Ibed85179284743dc8a9d1434f0c81626b0567e16 Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org> (cherry picked from commit be46f9f596c5172438a74759d48ca7db600cd737)