package/busybox: invert dependency with nmap

package/busybox: invert dependency with nmap

We only need that dependency when nmap's ncat is enabled.

For consistency, we add a dependency on nmap, not a suboption of it,
to have a dependency list in busybox that is only about packages, and
directly associates the upper-case package variable to the lower-case
package name, e.g. NMAP <-> nmap.

Thus, if BR2_PACKAGE_NMAP_NCAT is selected, we have a redundant
dependency. But that doesn't hurt and it really simplifies things.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Reviewed-by: Carlos Santos <casantos@datacom.com.br>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>