[lib][trusty] Add stack cookies to trusty apps

Trusty kernel initializes and maintains a random number pool.
The pool provides 16 bytes random number for each trusty app,
hence the trusty app use the random number as stack cookies.
The random number is allocated into trusty app's stack and
pointed by AT_RANDOM auxiliary variable.

Bug: 149518090
Test: Pass libc.stack_cookies in libc-test.
Change-Id: I5bf4e571ed35041cde6b33799210d948d519db1a
1 file changed