Update kernel to the latest mainline version without any Distro-upgrade?

To find out which kernel you have type uname -rin terminal.Now type this command to get list of available kernels.

apt-cache search linux-image

this will give you a very big output.Now chose one of them that you want to install and install it by following commands(Don't type these commands like this,replace the word kernal_version with the kernel version which you wish to install)

sudo apt-get install linux-image-kernal_version
sudo apt-get install linux-image-extra-kernal_version
sudo apt-get install linux-headers-kernal_version

Now in my case i choose linux-image-4.10.0-22-generic so my command will look like this

sudo apt-get install linux-image-4.10.0-22-generic 
sudo apt-get install linux-image-extra-4.10.0-22-generic
sudo apt-get install linux-headers-4.10.0-22-generic

now in the end remove old kernel by command

sudo apt-get autoremove

sudo reboot