lsof: needs mmu

Fixes:
http://autobuild.buildroot.net/results/f03/f03fd887cfb353149d88c97afa380bd95d6315f1/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/lsof/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_LSOF
 	bool "lsof"
+	depends on BR2_USE_MMU # fork()
 	help
 	  lsof (LiSt Open Files)
 	  The lsof tool lists information about files opened by