sysctl: fix false positives when PROC_SYSCTL=n

sysctl: fix false positives when PROC_SYSCTL=n

Having ->procname but not ->proc_handler is valid when PROC_SYSCTL=n,
people use such combination to reduce ifdefs with non-standard handlers.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=14408

Signed-off-by: Alexey Dobriyan <[email protected]>
Reported-by: Peter Teoh <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>