placement.c: make set_rectangle inline and drop unnecessary checks

With set_rectangle inline'd, the compile can produce more efficient code
and also proof the not-null test at compile time. This also makes the
extra check in callers unncessary. The compiler can even skip the whole
call (or inlined code path) if it can proof the rect parameter NULL.

Note: explicitly not using g_return_if_fail(), since is macro is designed
only as extra sanity check and can be switched to no-op at compile time.
(production builds potentially turn it off for smaller code, so it's
not at all reliable)

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
2 jobs for !44 with submit/placement-set_rectangle in 2 minutes and 44 seconds (queued for 54 seconds)
latest merge request