For the out-of-tree module build the kernel headers have to be installed. Then build the driver by running
#> make
in this directory.
To load the module from the build directory do
#> sudo modprobe videobuf2-vmalloc
#> sudo modprobe v43l2-mem2mem
#> sudo insmod musc
Or deploy first and auto-resolve module dependencies
#> sudo make install
#> sudo modprobe musc
A new device file /dev/musc should be available now.