board: remove references to TinyCrypt

Following the deprecation of TinyCrypt (#79566) we remove tags
referring to it.

Signed-off-by: Valerio Setti <[email protected]>

Author: valeriosetti

boards/96boards/avenger96/96b_avenger96.yaml

@@ -14,7 +14,6 @@ testing:
     - cmsis_rtos_v2
     - net
     - mpu
-    - tinycrypt
     - crypto
     - aes
     - cmm

boards/st/stm32mp157c_dk2/stm32mp157c_dk2.yaml

@@ -18,7 +18,6 @@ testing:
     - cmsis_rtos_v2
     - net
     - mpu
-    - tinycrypt
     - crypto
     - aes
     - cmm