esp_sha_wait_idle() function

This function does not ensure exclusive access to any SHA engine. Caller should use esp_sha_try_lock_engine() and esp_sha_lock_memory_block() as required. Functions declared in this header file wait for SHA engine completion automatically, so you don't need to use this API for these. However if accessing SHA registers directly, you will need to call this before accessing SHA registers if using the esp_sha_block() function. This function busy-waits, so wastes CPU resources. Best to delay calling until you are about to need it.