omac: fix accidentally reverted patch

introduced in 6816ac3f3fae776adb1372dbffd0441062006109
reverted in 8e7777b5545e46ab545bd51f7fcde7957134ade2

src/mac/omac/omac_process.c

@@ -27,7 +27,7 @@
 */
 int omac_process(omac_state *omac, const unsigned char *in, unsigned long inlen)
 {
-   unsigned long n, x, blklen;
+   unsigned long n, x;
    int           err;
 
    LTC_ARGCHK(omac  != NULL);
@@ -42,20 +42,23 @@ int omac_process(omac_state *omac, const unsigned char *in, unsigned long inlen)
    }
 
 #ifdef LTC_FAST
-   blklen = cipher_descriptor[omac->cipher_idx].block_length;
-   if (omac->buflen == 0 && inlen > blklen) {
-      unsigned long y;
-      for (x = 0; x < (inlen - blklen); x += blklen) {
-          for (y = 0; y < blklen; y += sizeof(LTC_FAST_TYPE)) {
-              *((LTC_FAST_TYPE*)(&omac->prev[y])) ^= *((LTC_FAST_TYPE*)(&in[y]));
-          }
-          in += blklen;
-          if ((err = cipher_descriptor[omac->cipher_idx].ecb_encrypt(omac->prev, omac->prev, &omac->key)) != CRYPT_OK) {
-             return err;
-          }
-      }
-      inlen -= x;
-    }
+   {
+     unsigned long blklen = cipher_descriptor[omac->cipher_idx].block_length;
+
+     if (omac->buflen == 0 && inlen > blklen) {
+        unsigned long y;
+        for (x = 0; x < (inlen - blklen); x += blklen) {
+            for (y = 0; y < blklen; y += sizeof(LTC_FAST_TYPE)) {
+                *((LTC_FAST_TYPE*)(&omac->prev[y])) ^= *((LTC_FAST_TYPE*)(&in[y]));
+            }
+            in += blklen;
+            if ((err = cipher_descriptor[omac->cipher_idx].ecb_encrypt(omac->prev, omac->prev, &omac->key)) != CRYPT_OK) {
+               return err;
+            }
+        }
+        inlen -= x;
+     }
+   }
 #endif
 
    while (inlen != 0) {