Refactor jemalloc_ffs*() into ffs_*().

Use appropriate versions to resolve 64-to-32-bit data loss warnings.

src/arena.c

@@ -3391,8 +3391,7 @@ bin_info_run_size_calc(arena_bin_info_t *bin_info)
 	 * be twice as large in order to maintain alignment.
 	 */
 	if (config_fill && unlikely(opt_redzone)) {
-		size_t align_min = ZU(1) << (jemalloc_ffs(bin_info->reg_size) -
-		    1);
+		size_t align_min = ZU(1) << (ffs_zu(bin_info->reg_size) - 1);
 		if (align_min <= REDZONE_MINSIZE) {
 			bin_info->redzone_size = REDZONE_MINSIZE;
 			pad_size = 0;

src/chunk.c

@@ -716,7 +716,7 @@ chunk_boot(void)
 	 * so pages_map will always take fast path.
 	 */
 	if (!opt_lg_chunk) {
-		opt_lg_chunk = jemalloc_ffs((int)info.dwAllocationGranularity)
+		opt_lg_chunk = ffs_u((unsigned)info.dwAllocationGranularity)
 		    - 1;
 	}
 #else