Revert "valgrind: add suppression for bug 472219"

This reverts commit 50f7214e09.

contrib/valgrind.supp

@@ -56,9 +56,3 @@
    ...
    fun:_ZN5BCLog6Logger12StartLoggingEv
 }
-{
-   Suppress https://bugs.kde.org/show_bug.cgi?id=472219 - fixed in Valgrind 3.22.
-   Memcheck:Param
-   ppoll(ufds.events)
-   obj:/lib/ld-musl-aarch64.so.1
-}