ifconfig: do not accept "ifconfig eth0 up 1.2.3.4/17" (ip with mask). Closes 5786

function                                             old     new   delta
ifconfig_main                                       1221    1237     +16

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
mdev: fix mode of dir1 in =dir1/dir2/file rule

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Merge git://busybox.net/busybox