grub-core/gnulib/rawmemchr.valgrind

# Suppress a valgrind message about use of uninitialized memory in rawmemchr().
# This use is OK because it provides only a speedup.
{
    rawmemchr-value4
    Memcheck:Value4
    fun:rawmemchr
}
{
    rawmemchr-value8
    Memcheck:Value8
    fun:rawmemchr
}