Revert "Move heap variable to all sha implementations"

This reverts commit a3f6bab.

Author: douzzer

wolfssl/wolfcrypt/sha.h

@@ -151,8 +151,8 @@ struct wc_Sha {
     #else
     word32  digest[WC_SHA_DIGEST_SIZE / sizeof(word32)];
     #endif
-#endif
     void*   heap;
+#endif
 #ifdef WOLFSSL_PIC32MZ_HASH
     hashUpdCache cache; /* cache for updates */
 #endif

wolfssl/wolfcrypt/sha256.h

@@ -194,13 +194,13 @@ struct wc_Sha256 {
     word32  buffLen;   /* in bytes          */
     word32  loLen;     /* length in bytes   */
     word32  hiLen;     /* length in bytes   */
+    void*   heap;
 
 #ifdef WC_C_DYNAMIC_FALLBACK
     int sha_method;
 #endif
 
 #endif
-    void*   heap;
 #ifdef WOLFSSL_PIC32MZ_HASH
     hashUpdCache cache; /* cache for updates */
 #endif

wolfssl/wolfcrypt/sha512.h

@@ -144,7 +144,6 @@ struct wc_Sha512 {
     cy_stc_crypto_sha_state_t hash_state;
     cy_en_crypto_sha_mode_t sha_mode;
     cy_stc_crypto_v2_sha512_buffers_t sha_buffers;
-    void*   heap;
 #else
     word64  digest[WC_SHA512_DIGEST_SIZE / sizeof(word64)];
     word64  buffer[WC_SHA512_BLOCK_SIZE  / sizeof(word64)];