avutil/aes: document some missing arguments

libavutil/aes.h

@@ -42,6 +42,9 @@ struct AVAES *av_aes_alloc(void);
 
 /**
  * Initialize an AVAES context.
+ *
+ * @param a The AVAES context
+ * @param key Pointer to the key
  * @param key_bits 128, 192 or 256
  * @param decrypt 0 for encryption, 1 for decryption
  */
@@ -49,9 +52,11 @@ int av_aes_init(struct AVAES *a, const uint8_t *key, int key_bits, int decrypt);
 
 /**
  * Encrypt or decrypt a buffer using a previously initialized context.
- * @param count number of 16 byte blocks
+ *
+ * @param a The AVAES context
  * @param dst destination array, can be equal to src
  * @param src source array, can be equal to dst
+ * @param count number of 16 byte blocks
  * @param iv initialization vector for CBC mode, if NULL then ECB will be used
  * @param decrypt 0 for encryption, 1 for decryption
  */