Hi,
Before End of life, there will be announcement for EOS date. Once they announce, usually, 5 years time will be available to become EOL. During those 5 years support can remain valid if renewed periodically during define time-lines. After EOL, no more support will be available. But still no EOS announced :)
So if you already have 2110, then you should not worry about but if you are looking to buy it, then i would suggest you to go with Firepower 1140 or new one 1150 ( 1150 HAVE 10g sfp+ also ). These hardware are announced last year around june and offer better hardware and performance.