Fix a fairly common typo in comments
diff --git a/include/mbedtls/pkcs11.h b/include/mbedtls/pkcs11.h
index aa549fd..7632929 100644
--- a/include/mbedtls/pkcs11.h
+++ b/include/mbedtls/pkcs11.h
@@ -54,7 +54,7 @@
 } mbedtls_pkcs11_context;
 
 /**
- * Initialize a mbetls_pkcs11_context.
+ * Initialize a mbedtls_pkcs11_context.
  * (Just making memory references valid.)
  */
 void mbedtls_pkcs11_init( mbedtls_pkcs11_context *ctx );