ASoC: soc-topology: cleanup cppcheck warning at soc_tplg_process_headers()

This patch cleanups below cppcheck warning.

sound/soc/soc-topology.c:2576:27: style: The scope of the variable 'hdr' can be reduced. [variableScope]
 struct snd_soc_tplg_hdr *hdr;
                          ^
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87sfzswflw.wl-kuninori.morimoto.gx@renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-topology.c

@@ -2572,13 +2572,13 @@ static int soc_tplg_load_header(struct soc_tplg *tplg,
 /* process the topology file headers */
 static int soc_tplg_process_headers(struct soc_tplg *tplg)
 {
-	struct snd_soc_tplg_hdr *hdr;
 	int ret;
 
 	tplg->pass = SOC_TPLG_PASS_START;
 
 	/* process the header types from start to end */
 	while (tplg->pass <= SOC_TPLG_PASS_END) {
+		struct snd_soc_tplg_hdr *hdr;
 
 		tplg->hdr_pos = tplg->fw->data;
 		hdr = (struct snd_soc_tplg_hdr *)tplg->hdr_pos;