cc3xx: Add RNG test cases

This adds test cases for TRNG:
- Verifies correct entropy generation in both EHR and DMA modes.
- Measures TRNG generation and copy speed for different entropy sizes.
- Measures DRBG generation and copy speed for different entropy sizes.
- Stress tests the TRNG resilience in handling errors.
- Tests RNG SRAM read / write logic.

Signed-off-by: Amjad Ouled-Ameur <amjad.ouled-ameur@arm.com>
Change-Id: Iaa0cadd525ec8c7dc5c5655a867ed0ce1ae21ce7
4 files changed