ASoC: SOF: Disable pointless writes to debugfs file

The permissions on this debugfs file are 0444 so it can't be written to.
And writing to the file hasn't done anything since commit 6e9548cdb3
("ASoC: SOF: Convert the generic IPC flood test into SOF client").
Delete the write function.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://msgid.link/r/9d2477cf-25aa-4d12-818f-fdafc9aaa28a@moroto.mountain
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/debug.c

@@ -19,24 +19,6 @@
 #include "sof-priv.h"
 #include "ops.h"
 
-static ssize_t sof_dfsentry_write(struct file *file, const char __user *buffer,
-				  size_t count, loff_t *ppos)
-{
-	size_t size;
-	char *string;
-	int ret;
-
-	string = kzalloc(count+1, GFP_KERNEL);
-	if (!string)
-		return -ENOMEM;
-
-	size = simple_write_to_buffer(string, count, ppos, buffer, count);
-	ret = size;
-
-	kfree(string);
-	return ret;
-}
-
 static ssize_t sof_dfsentry_read(struct file *file, char __user *buffer,
 				 size_t count, loff_t *ppos)
 {
@@ -126,7 +108,6 @@ static const struct file_operations sof_dfs_fops = {
 	.open = simple_open,
 	.read = sof_dfsentry_read,
 	.llseek = default_llseek,
-	.write = sof_dfsentry_write,
 };
 
 /* create FS entry for debug files that can expose DSP memories, registers */