Define _NPCM and the last PC_FREEn constant in terms of _NPCPV.

This applies one of the changes from
5567d6b441 to other architectures
besides arm64.

Reviewed by:	kib
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D36263

sys/arm/arm/pmap-v6.c

@@ -2753,7 +2753,7 @@ pv_to_chunk(pv_entry_t pv)
 #define PV_PMAP(pv) (pv_to_chunk(pv)->pc_pmap)
 
 #define	PC_FREE0_9	0xfffffffful	/* Free values for index 0 through 9 */
-#define	PC_FREE10	0x0000fffful	/* Free values for index 10 */
+#define	PC_FREE10	((1ul << (_NPCPV % 32)) - 1)	/* Free values for index 10 */
 
 static const uint32_t pc_freemask[_NPCM] = {
 	PC_FREE0_9, PC_FREE0_9, PC_FREE0_9,

sys/arm/include/pmap-v6.h

@@ -143,8 +143,9 @@ typedef struct pv_entry {
  * pv_entries are allocated in chunks per-process.  This avoids the
  * need to track per-pmap assignments.
  */
-#define	_NPCM	11
 #define	_NPCPV	336
+#define	_NPCM	howmany(_NPCPV, 32)
+
 struct pv_chunk {
 	pmap_t			pc_pmap;
 	TAILQ_ENTRY(pv_chunk)	pc_list;