libcap: import from packages feed

Having libcap in OpenWrt base allows us to enable libcap support in
other packages in base.

In lldpd, this would allow the monitor process to drop its privileges
instead of running as root, improving security. It will also allow us to
drop our patch to disable libcap.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>

package/libs/libcap/patches/300-disable-tests.patch

@@ -0,0 +1,10 @@
+--- a/Makefile
++++ b/Makefile
+@@ -17,7 +17,6 @@ ifeq ($(GOLANG),yes)
+ 	$(MAKE) -C go $@
+ 	rm -f cap/go.sum
+ endif
+-	$(MAKE) -C tests $@
+ 	$(MAKE) -C progs $@
+ 	$(MAKE) -C doc $@
+ 	$(MAKE) -C kdebug $@