ASoC: qdsp6: q6adm: fix cppcheck warnings for unnecessary initialization

cppcheck reports below warning.

q6adm.c:475]: (style) Variable 'matrix_map' is reassigned a value before the
old one has been used.

This is due to unnecessary initialization of variable matrix_map, which is
now removed as part of this patch.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210809123137.14456-3-srinivas.kandagatla@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/qcom/qdsp6/q6adm.c

@@ -465,7 +465,7 @@ int q6adm_matrix_map(struct device *dev, int path,
 	struct apr_pkt *pkt;
 	uint16_t *copps_list;
 	int pkt_size, ret, i, copp_idx;
-	void *matrix_map = NULL;
+	void *matrix_map;
 	struct q6copp *copp;
 
 	/* Assumes port_ids have already been validated during adm_open */