nmap: update license

nmap is licensed under GPL-2.0 but with additional restrictions (see
COPYING, especially the "IMPORTANT NMAP LICENSE TERMS" part).

So, following advices of Yann and Arnout (see
https://patchwork.ozlabs.org/patch/979081), set license to nmap license

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit f6199d3654d0a78d8ac5557679086e8618132854)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/nmap/nmap.mk

@@ -10,7 +10,7 @@ NMAP_SOURCE = nmap-$(NMAP_VERSION).tar.bz2
 NMAP_DEPENDENCIES = libpcap
 NMAP_CONF_OPTS = --without-liblua --without-zenmap \
 	--with-libdnet=included --with-liblinear=included
-NMAP_LICENSE = GPL-2.0
+NMAP_LICENSE = nmap license
 NMAP_LICENSE_FILES = COPYING
 
 # needed by libpcap