Redefine MAX_FEATURES to 64 for minor performance improvement.

Bitstrings are handled as 64bits and bit_ffs()/bit_fls() are faster on
whole words.

Bug 9537

src/slurmctld/node_scheduler.c

@@ -84,7 +84,7 @@
 #include "src/slurmctld/slurmctld_plugstack.h"
 
 #define _DEBUG	0
-#define MAX_FEATURES  32	/* max exclusive features "[fs1|fs2]"=2 */
+#define MAX_FEATURES  64	/* max exclusive features "[fs1|fs2]"=2 */
 
 struct node_set {		/* set of nodes with same configuration */
 	uint16_t cpus_per_node;	/* NOTE: This is the minimum count */