atomisp: remove another layer of allocator indirection

Our driver only ever uses one set of routines for the allocators used by the CSS layer to
manage memory and the memory management on the ISP. We can thus remove the function vectors
and simply call the intended routines directly.

These routines in turn are simply wrappers around another layer of code so remove this
second layer of wrappers and call the hrt methods directly. In time we can remove this layer
of indirection as well.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>