ASoC: stm32: sai: fix master clock naming

Fixes: 8307b2afd386 ("ASoC: stm32: sai: set sai as mclk clock provider")

Fix warning issued by strncat when bound equals to source length.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/stm/stm32_sai_sub.c

@@ -404,12 +404,11 @@ static int stm32_sai_add_mclk_provider(struct stm32_sai_sub_data *sai)
 	 * String after "_" char is stripped in parent name.
 	 */
 	p = mclk_name;
-	while (*s && *s != '_' && (i < (SAI_MCLK_NAME_LEN - 6))) {
+	while (*s && *s != '_' && (i < (SAI_MCLK_NAME_LEN - 7))) {
 		*p++ = *s++;
 		i++;
 	}
-	STM_SAI_IS_SUB_A(sai) ?
-		strncat(p, "a_mclk", 6) : strncat(p, "b_mclk", 6);
+	STM_SAI_IS_SUB_A(sai) ? strcat(p, "a_mclk") : strcat(p, "b_mclk");
 
 	mclk->hw.init = CLK_HW_INIT(mclk_name, pname, &mclk_ops, 0);
 	mclk->sai_data = sai;