ASoC: SOF: ipc3-loader: Handle PROBE_INFO ext_manifest

Merge series from Peter Ujfalusi <peter.ujfalusi@linux.intel.com>:

The PROBE_INFO (ext_manifest type 3) is not used by the kernel, but
at every tiem the firmware is loaded the following is printed in
info level (user visible):
unknown sof_ext_man header type 3 size 0x30

The type is known, but it is not handled, the print is misleading.