net: udp: Adjust UDP socket state for encapsulation sockets

UDP IPv4 encapsulation sockets will have their state printed as 0xF0
binary ORed with the actual state such that they can be distinguished
from regular UDP sockets in /proc/net/udp.

CRs-Fixed: 2333588
Change-Id: I240ab1526a4280e5e996d9577a904581684fc84a
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>