Use devm_kzalloc function to simplify driver error path. This function
is a per driver/device memory management function that will auto free
any memory when driver is released.
Currently do not have interrupts defined in hardware and thus they are
not defined in the devicetree. Since the code/kernel thinks there should
be interrupts defined in the devicetree node it throws an error when
there is not. There should be a better way to do this but this works for
now.
