audio: export symbols for LLEXT module compatibility

This patch exports the symbols `comp_is_current_data_blob_valid` and
`ipc4_update_source_format` to resolve issues encountered when the
Google RTC module was converted into an LLEXT module. The lack of
exported symbols was causing warnings and subsequent firmware exceptions
when these functions were called from within the module.

Changes include:
- Adding `EXPORT_SYMBOL` for `comp_is_current_data_blob_valid` in
  src/audio/data_blob.c.
- Adding `EXPORT_SYMBOL` for `ipc4_update_source_format` in
  src/ipc/ipc4/helper.c.

Signed-off-by: Tomasz Leman <tomasz.m.leman@intel.com>

Author: tmleman

src/audio/data_blob.c

@@ -128,6 +128,7 @@ bool comp_is_current_data_blob_valid(struct comp_data_blob_handler
 {
 	return !!blob_handler->data;
 }
+EXPORT_SYMBOL(comp_is_current_data_blob_valid);
 
 int comp_init_data_blob(struct comp_data_blob_handler *blob_handler,
 			uint32_t size, const void *init_data)

src/ipc/ipc4/helper.c

@@ -1218,6 +1218,7 @@ void ipc4_update_source_format(struct sof_source *source,
 	source_set_valid_fmt(source, valid_fmt);
 	source_set_buffer_fmt(source, fmt->interleaving_style);
 }
+EXPORT_SYMBOL(ipc4_update_source_format);
 
 void ipc4_update_sink_format(struct sof_sink *sink,
 			     const struct ipc4_audio_format *fmt)