iprutils: uses fork(), needs MMU

Fixes:

  http://autobuild.buildroot.net/results/6ee89f9a4e05c89375a96ac7085747afc301b896/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/iprutils/Config.in

@@ -6,6 +6,7 @@ config BR2_PACKAGE_IPRUTILS
 	select BR2_PACKAGE_NCURSES_TARGET_MENU
 	select BR2_PACKAGE_LIBSYSFS
 	select BR2_PACKAGE_PCIUTILS
+	depends on BR2_USE_MMU # fork()
 	depends on !BR2_bfin # pciutils
 	help
 	  System utilities for IBM Power RAID devices