kconfig: don't allocate n+1 elements in temporary array

The temporary array that stores the search results is not NULL-terminated,
so there is no reason to allocate n+1 elements.

Reported-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Reviewed-by: Jean Delvare <jdelvare@suse.de>