optimize hash-drbg layout, save 12 bytes on 64bit

wolfcrypt/src/random.c

@@ -149,11 +149,11 @@ enum {
 
 typedef struct DRBG {
     Sha256 sha;
+    word32 reseedCtr;
+    word32 lastBlock;
     byte digest[SHA256_DIGEST_SIZE];
     byte V[DRBG_SEED_LEN];
     byte C[DRBG_SEED_LEN];
-    word32 reseedCtr;
-    word32 lastBlock;
     byte   matchCount;
 } DRBG;
 

wolfssl/wolfcrypt/random.h

@@ -82,8 +82,8 @@ struct DRBG; /* Private DRBG state */
 
 /* Hash-based Deterministic Random Bit Generator */
 typedef struct RNG {
-    OS_Seed seed;
     struct DRBG* drbg;
+    OS_Seed seed;
     byte status;
 } RNG;