Move MBEDTLS_ERR_xxx Doxygen comments before the definition

Now that descriptions of error codes no longer have to be on the same line
for the sake of generate_errors.pl, move them to their own line before the
definition. This aligns them with what we do for other definitions, and
means that we no longer need to have very long lines containing both the C
definition and the comment.

```
perl -i -pe 's~^(#define +MBEDTLS_ERR_\w+ +-\w+) */\*[*!]<(.*)\*/~/**$2*/\n$1~' include/mbedtls/*.h
```

This commit does not change the output of generate_errors.pl.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/include/mbedtls/camellia.h b/include/mbedtls/camellia.h
index 6a09da8..6feeaf0 100644
--- a/include/mbedtls/camellia.h
+++ b/include/mbedtls/camellia.h
@@ -33,9 +33,11 @@
 #define MBEDTLS_CAMELLIA_ENCRYPT     1
 #define MBEDTLS_CAMELLIA_DECRYPT     0
 
-#define MBEDTLS_ERR_CAMELLIA_BAD_INPUT_DATA -0x0024 /**< Bad input data. */
+/** Bad input data. */
+#define MBEDTLS_ERR_CAMELLIA_BAD_INPUT_DATA -0x0024
 
-#define MBEDTLS_ERR_CAMELLIA_INVALID_INPUT_LENGTH -0x0026 /**< Invalid data input length. */
+/** Invalid data input length. */
+#define MBEDTLS_ERR_CAMELLIA_INVALID_INPUT_LENGTH -0x0026
 
 #ifdef __cplusplus
 extern "C" {