Fixes: the png_handle_cHRM crash bug in bundled libpng 1.5.4

Fixes: the png_handle_cHRM crash bug in bundled libpng 1.5.4

The PNG Development Group explains that libpng 1.5.4 (only) introduced
a divide-by-zero bug in png_handle_cHRM(), which could lead to crashes
(denial of service) for certain malformed PNGs.
Ref. http://www.libpng.org/pub/png/libpng.html

This commit contains the patch recommended by the PNG Development
Group, ref. http://www.kb.cert.org/vuls/id/477046

Task-number: QTBUG-22168

(cherry picked from commit 55c2ea18c522bd8700f43884124e02b460cdb5e2)