crypto: doc - Fix typo in crypto-API.xml

This patch fix some typos found in crypto-API.xml.
It is because the file is generated from comments in sources,
so I had to fix typo in sources.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/include/crypto/rng.h b/include/crypto/rng.h
index c5d4684..b95ede3 100644
--- a/include/crypto/rng.h
+++ b/include/crypto/rng.h
@@ -28,7 +28,7 @@
  *		if provided to the call.
  * @seed:	Seed or reseed the random number generator.  With the
  *		invocation of this function call, the random number
- *		generator shall become ready fo generation.  If the
+ *		generator shall become ready for generation.  If the
  *		random number generator requires a seed for setting
  *		up a new state, the seed must be provided by the
  *		consumer while invoking this function. The required