Remove wrong freshness check from build/update-setup-h script.

This didn't work correctly if a header was updated from its corresponding
setup0.h first as it was then newer than include/wx/msw/setup_inc.h even
though it had been older than it at the start of the script execution.

Just keep things simple and get rid of the check.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77710 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

build/update-setup-h

@@ -55,11 +55,6 @@ update_single_setup_h()
     setup_inc=$1
     shift
 
-    if [ $setup_inc -ot $1 ]; then
-        echo "Skipping $1 which is already up to date."
-        return 0
-    fi
-
     echo -n "Updating $1 ..."
 
     tmp=$i.$$.tmp