gpu: ion: tegra: Ignore unsupported heap with printing warning

Instead of rewinding and returning error for unsupported heap,
continuie to next heap with printing warning. If some kind of heap
isn't supported, it doesn't have to cancel Ion memory manager itself.

Change-Id: I0d2c8dc1b9fc69318309f90dc657b10a3bd866bb
Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
Reviewed-on: http://git-master/r/73607
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Krishna Reddy <vdumpa@nvidia.com>