The heap, plus a few globals relevant to mbedtls get put in
their own memory partition.
With systems that have power-of-two region size/alignment
constraints, this results in a 64K partition being created,
even though we are using just a whisker above 32K.
Lower the heap size a little so everything fits in 32K.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
90132d3543