kernel: Mark function as static in kernel/seccomp.c

Mark function as static in kernel/seccomp.c because it is not used
outside this file.

This eliminates the following warning in kernel/seccomp.c:
kernel/seccomp.c:296:6: warning: no previous prototype for ?seccomp_attach_user_filter? [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <[email protected]>
Reviewed-by: Josh Triplett <[email protected]>
Acked-by: Kees Cook <[email protected]>
Acked-by: Will Drewry <[email protected]>
Signed-off-by: James Morris <[email protected]>

kernel/seccomp.c

@@ -293,7 +293,7 @@ static long seccomp_attach_filter(struct sock_fprog *fprog)
  *
  * Returns 0 on success and non-zero otherwise.
  */
-long seccomp_attach_user_filter(char __user *user_filter)
+static long seccomp_attach_user_filter(char __user *user_filter)
 {
 	struct sock_fprog fprog;
 	long ret = -EFAULT;