Unable to run run-time loaded code on ZedBoard

[Patrick Gauvin]

> Hmm maybe a data cache flush and instruction cache invalidate is needed.
>
> Maybe the L2 cache support being added has broken this test.

I added calls to rtems_cache_invalidate_entire_data and
rtems_cache_invalidate_entire_instruction before calling the loaded
functions (dl-load.c:54) and they now work as expected.

I haven't looked too much at the internals of the RTL code, but should
instruction and data cache invalidates be performed in the RTL code on
the memory regions where objects are loaded, or is this a bug
somewhere else? I'm willing to help with patching/testing for this
since I have the hardware easily available.

Thank you,

Patrick