This is a great question but I believe the answer is no. The reason for defragmenting a spinning platter hard drive is so that all sectors of the files are in contiguous order or as close to each other as possible for each file or program. In other words, sector one would be followed immediately by sector two, then sector 3 and so on, and all the read/write head needs to do is follow along the straight circular path until the next sector in order makes its way around the spinning disc to it. Once all the sectors in order have been retrieved from the track the head is on, it then only needs to move one track over to begin collecting the next sectors in order. It continues this process until it's retrieved all necessary sectors. This facilitates faster access due to the moving read/write heads not having to scatter all over the place to pick up the sectors one at a time from different locations on the platter(s).
Since the "hard drive" in your phone (i.e. SD Card or SD Ram), is a solid state storage, there are no moving parts. This means that in order for the computer (yes, I said computer - that's what these phones are now), to retrieve the necessary data or program file, it only needs to know what sector on the memory chip it has to pull from to obtain the data. Since these individual addresses for the sectors are nothing more than a number, it's simple and doesn't require but mere nanoseconds more time to get the separate parts from different sections of the chip and compile them into one long string of data.
