[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>
6 files changed