Suffix rules are the old-fashioned way of defining implicit rules for make.
We don't need them as we generate explicit rules for all sources we build.
[ChangeLog][qmake] Makefile output no longer contains implicit
suffix rules, as all sources are built using explicit rules.
Change-Id: I4ecfa5b80c8ae33aea8730836f3baf99dd4951dd
Task-number: QTBUG-30813
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>