Minor cleanup in widget.c

* src/widget.c (update_wm_hints): Remove variables that are
always zero, and simplify all expressions which used them.
1 job for master in 51 minutes and 41 seconds (queued for 3 seconds)
Status Job ID Name Coverage
failed #1227


Name Stage Failure
test-all Test
Makefile:313: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:288: recipe for target 'check-expensive' failed
make[1]: *** [check-expensive] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
Makefile:962: recipe for target 'check-expensive' failed
make: *** [check-expensive] Error 2
ERROR: Job failed: exit code 1