[qca-nss-drv] Fix compile error when referencing ctl_table structure

While referencing ctl_table structure from Linux Kernel, the "struct"
identifier is missing and causes compile error

Change-Id: Ie1ca04947625959607f9493c8e0761095a49c045
Signed-off-by: Stephen Wang <wstephen@codeaurora.org>
diff --git a/nss_log.c b/nss_log.c
index bad5aed..478fdfe 100644
--- a/nss_log.c
+++ b/nss_log.c
@@ -611,7 +611,7 @@
  * nss_logbuffer_handler()
  *	Enable NSS debug output
  */
-int nss_logbuffer_handler(ctl_table *ctl, int write, void __user *buffer, size_t *lenp, loff_t *ppos)
+int nss_logbuffer_handler(struct ctl_table *ctl, int write, void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 	int i;