ASoC: topology: Fix route memory corruption

Merge series from Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>:

Originally reported here:
https://github.com/thesofproject/avs-topology-xml/issues/22#issuecomment-2127892605
There is various level of failure there, first of all when topology
loads routes, it points directly into FW file, but it may be freed after
topology load. After fixing the above, when avs driver parses topology
it should allocate its own memory, as target strings can be shorter than
needed. Also clean up soc_tplg_dapm_graph_elems_load() a bit.