Shoots Down Ngannou vs. Fury

Those of you who wanna see Francis Ngannou box Tyson Fury -- the world's best heavyweight fighter -- ear muffs ... 'cause Dana White tells TMZ Sports it's just silly talk.

"Nobody is beating my door down for this fight. And I love Tyson Fury, I'm friends with Tyson. He's one of the greatest boxers of all time. One of the greatest heavyweight boxers of all time going in against one of my MMA guys. We saw this movie before. We know how this story ends," the UFC president plainly told us.

There's been some discussion around Francis and Tyson boxing in the past ... but it really heated up once Ngannou went into the ring following Fury's brutal 6th round knockout of fellow British heavyweight star…