Prior to this commit, it wasn't possible to load ELF modules from
the external PSRAM. There were two main issues about it: 1) copying
data using the instruction bus was being used instead of the data
bus (this, per si, isn't a problem, but requires special attention
regarding data alignment), and 2) the cache was not being properly
cleaned and flushed to properly access the loaded data using the
instruction bus.
Signed-off-by: Tiago Medicci Serrano <tiago.medicci@espressif.com>