crypto: caam - Provide the name of the function and provide missing descriptions

Fixes the following W=1 kernel build warning(s):

 drivers/crypto/caam/caampkc.c:199: warning: expecting prototype for from a given scatterlist(). Prototype was for caam_rsa_count_leading_zeros() instead
 drivers/crypto/caam/caamalg_qi2.c:87: warning: Function parameter or member 'xts_key_fallback' not described in 'caam_ctx'
 drivers/crypto/caam/caamalg_qi2.c:87: warning: Function parameter or member 'fallback' not described in 'caam_ctx'

Cc: "Horia Geantă" <horia.geanta@nxp.com>
Cc: Aymen Sghaier <aymen.sghaier@nxp.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/caamalg_qi2.c

@@ -71,6 +71,9 @@ struct caam_skcipher_alg {
  * @adata: authentication algorithm details
  * @cdata: encryption algorithm details
  * @authsize: authentication tag (a.k.a. ICV / MAC) size
+ * @xts_key_fallback: true if fallback tfm needs to be used due
+ *		      to unsupported xts key lengths
+ * @fallback: xts fallback tfm
  */
 struct caam_ctx {
 	struct caam_flc flc[NUM_OP];

drivers/crypto/caam/caampkc.c

@@ -187,7 +187,8 @@ static void rsa_priv_f_done(struct device *dev, u32 *desc, u32 err,
 }
 
 /**
- * Count leading zeros, need it to strip, from a given scatterlist
+ * caam_rsa_count_leading_zeros - Count leading zeros, need it to strip,
+ *                                from a given scatterlist
  *
  * @sgl   : scatterlist to count zeros from
  * @nbytes: number of zeros, in bytes, to strip