Squashed commit of the following:
sched/sched/sched_getsockets.c: Fix an error in conditional compilation.
fs/: Remove all conditional logic based on CONFIG_NSOCKET_DESCRIPTORS == 0
Documentation/: Remove all references to CONFIG_NSOCKET_DESCRIPTORS == 0
include/: Remove all conditional logic based on CONFIG_NSOCKET_DESCRIPTORS == 0
libs/: Remove all conditional logic based on CONFIG_NSOCKET_DESCRIPTORS == 0
net/: Remove all conditional logic based on CONFIG_NSOCKET_DESCRIPTORS == 0
sched/: Remove all conditional logic based on CONFIG_NSOCKET_DESCRIPTORS == 0
syscall/: Remove all conditional logic based on CONFIG_NSOCKET_DESCRIPTORS == 0
tools/: Fixups for CONFIG_NSOCKET_DESCRIPTORS no longer used to disable sockets.
net/netdev: Add implementation of if_nametoindex() and if indextoname().
net/pkt: Raw AF_PACKET sockets now depend on CONFIG_NETDEV_IFINDEX.
net/procfs: Tweak to handle traversal of interfaces if CONFIG_NETDEV_IFINDEX is not defined.
net/netdev.h: Update netdev_findbyaddr() to use the assigned device index.
Trivial typo fix
net/netdev: Add support for assigned an interface index to a device when it is regisgtered.
