package/radvd: drop dependency on flex runtime library

Radvd has its own main(), and does not use yywrap() from libfl.so,
because scanner.l module contains noyywrap option. So, none of the
functions exported by libfl.so are used, and there's no need to have
the flex runtime on target.

Signed-off-by: Alexander Mukhin <alexander.i.mukhin@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 6274868bd12d86a1e4d58f7a7a479ba76ff56532)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/radvd/Config.in

@@ -1,7 +1,6 @@
 config BR2_PACKAGE_RADVD
 	bool "radvd"
 	depends on BR2_USE_MMU # fork()
-	select BR2_PACKAGE_FLEX
 	help
 	  IPv6 Router Advertisement Daemon.
 

package/radvd/radvd.mk

@@ -6,7 +6,7 @@
 
 RADVD_VERSION = 2.18
 RADVD_SITE = http://www.litech.org/radvd/dist
-RADVD_DEPENDENCIES = host-bison flex host-flex host-pkgconf
+RADVD_DEPENDENCIES = host-bison host-flex host-pkgconf
 # We need to ignore <linux/if_arp.h>, because radvd already includes
 # <net/if_arp.h>, which conflicts with <linux/if_arp.h>.
 RADVD_CONF_ENV = \