client: clientGetWMNormalHints(): simplify defaults and constraints

Applying constraints and defaults for missing/broken values can be
written more compact using MIN()/MAX() macros. As a nice side effect,
the compiler can generate more efficient code for that, even though
practially not noticed on such a rarely called cold path.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
2 jobs for !88 with submit/clientGetWMNormalHints_simplify_minmax in 2 minutes and 50 seconds (queued for 3 seconds)
latest merge request