Temporarily disable shared Mbed TLS heap for SGM

There is a bug in the shared heap implementation for SGM. Until the bug
is solved, the default implementation is used.

Change-Id: I010911a3f00ed860f742b14daad1d99b9e7ce711
Signed-off-by: John Tsichritzis <john.tsichritzis@arm.com>
1 file changed