drivers/platform/x86/amd: pmf: Check for invalid sideloaded Smart PC Policies

If a policy is passed into amd_pmf_get_pb_data() that causes the engine
to fail to start there is a memory leak. Free the memory in this failure
path.

Fixes: 10817f2 ("platform/x86/amd/pmf: Add capability to sideload of policy binary")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20250423132002.3984997-2-superm1@kernel.org
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Author: superm1

drivers/platform/x86/amd/pmf/tee-if.c

@@ -364,9 +364,14 @@ static ssize_t amd_pmf_get_pb_data(struct file *filp, const char __user *buf,
 	amd_pmf_hex_dump_pb(dev);
 	ret = amd_pmf_start_policy_engine(dev);
 	if (ret < 0)
-		return ret;
+		goto cleanup;
 
 	return length;
+
+cleanup:
+	kfree(dev->policy_buf);
+	dev->policy_buf = NULL;
+	return ret;
 }
 
 static const struct file_operations pb_fops = {