[IPV4]: Create ipv4_is_<type>(__be32 addr) functions

Change IPV4 specific macros LOOPBACK MULTICAST LOCAL_MCAST BADCLASS
and ZERONET macros to inline functions ipv4_is_<type>(__be32 addr)

Adds type safety and arguably some readability.

Changes since last submission:

Removed ipv4_addr_octets function
Used hex constants
Converted recently added rfc3330 macros

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>