They have the same meaning but slightly different tones.
"I'll keep my calendar clear." -> (好的) I'll make sure I'll be available
(through someone else's request to do something) "I'll make enough time out of my calendar." -> (好吧) I'm quite busy, but I'll try to be available
(from own wishes to do something) "I'll make enough time out of my calendar." -> It's okay, even though I'm busy, I want to do this enough to make some time
That's the general vibe I get from the sentences, it would depend on the person though