fbset: needs host-bison and host-flex

Fixes:
http://autobuild.buildroot.net/results/08d6d70f7c89617c20e727e77e0f6be09974dfc1/



Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Acked-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Tested-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>