Fix guard around alloc_hugetlb, fixes compile warning

The warning was:
```
/home/rgommers/code/pixi-dev-scipystack/openblas/OpenBLAS/driver/others/memory.c: At top level:
/home/rgommers/code/pixi-dev-scipystack/openblas/OpenBLAS/driver/others/memory.c:2565:14: warning: 'alloc_hugetlb' defined but not used [-Wunused-function]
 2565 | static void *alloc_hugetlb(void *address){
      |              ^~~~~~~~~~~~~
```

The added define is the same as is already present in the TLS part of
`memory.c`. This follows up on OpenMathLibgh-4681.

driver/others/memory.c

@@ -2538,7 +2538,7 @@ static void *alloc_shm(void *address){
 }
 #endif
 
-#if defined OS_LINUX  || defined OS_AIX  || defined __sun__  || defined OS_WINDOWS
+#if ((defined ALLOC_HUGETLB) && (defined OS_LINUX  || defined OS_AIX  || defined __sun__  || defined OS_WINDOWS))
 
 static void alloc_hugetlb_free(struct release_t *release){