Python's sets are not deterministic.
`devices` were already sorted but `dev_supports` is still a
non-deterministic set. Sort dev_supports to make the graph output
deterministic.
Fixes commit 29942475c5 ("scripts: gen_handles: output dependency graph")
It is quite ironic that this initial and non-deterministic graph commit
was concurrent with and slightly delayed other commit
f896fc2306 ("scripts: gen_handles: Sort the device handles") which
fixed another, similar non-determinism issue in the same area. A true
"whack-a-mole"!
Signed-off-by: Marc Herbert <marc.herbert@intel.com>