What if.... (In my opinion)

That would be a dumb idea if they did that honestly, would make no sense.

And if you havent seen a real tsunami before, that tsunami in the trailer was nothing compared to Japan's tsunamis

Oh sure, Godzilla loves hitching free rides on Tsunami waves whenever they occur, they are like the taxi service for Godzilla, bringing him about on a sight-seeing tour around the world in search of chicks. And then the Mutos travel using the typhoon on land to go about their killing spree. 

Look like I've posted something stupid :( I'm sorry...

I don't think it's all that stupid of an idea. I mean the water is going above trees(granted palm trees which don't get too big, but still). Unless godzilla rushed out of the water, and judging by the rate he's going when they shoot the flares up I don't see him bringing that much water forward. However due to the fact the MUTO is in hawaii I don't think a tsunami would coincidentally show up and bring Godzilla to it, but I see your reasoning behind thinking it. 

i dont think it was stupied but i dont think it is true

not sure if op is serious or just an absolute moron

I am no physics expert, but something of Godzilla's size could very well create a tsunami depending on how fast he was swimming.

The sheer volume of displaced water for a creature of Godzilla's size is staggering to contemplate. Again, I'm not a physics expert nor do I have any calculations for you, but here's an example to use. Take a bath and be sure to block the water from draining in whatever way you can. Fill it to the brim while your in the tub, and then stand up and get out.

How much water is left?

Now imagine that phenomenon on a creature that's 350 feet high and weighing god only knows how much. The water displacement off of Godzilla's body while moving at speed would easily create a small tsunami such as the one we're seeing in the trailer. It might not be quite as big as the one in the movie, but it would create a small one for sure.