driver: i2s: fix i2s_mcux_sai build warning

remove unused args

fixing: #42179

Signed-off-by: Hake Huang <hake.huang@oss.nxp.com>
diff --git a/drivers/i2s/i2s_mcux_sai.c b/drivers/i2s/i2s_mcux_sai.c
index 9a75718..5692b03 100644
--- a/drivers/i2s/i2s_mcux_sai.c
+++ b/drivers/i2s/i2s_mcux_sai.c
@@ -328,7 +328,6 @@
 	const struct i2s_mcux_config *dev_cfg = dev->config;
 	uint32_t offset = dev_cfg->mclk_pin_offset;
 	uint32_t mask = dev_cfg->mclk_pin_mask;
-	uint32_t value = 0;
 	uint32_t *gpr =  (uint32_t *)DT_REG_ADDR(DT_NODELABEL(iomuxcgpr)) + offset;
 
 	if (dir) {