Re-instate UMA cached backend for 4K - 64K allocations. New consumers

like geli(4) uses malloc(9) to allocate temporary buffers that gets
free'ed shortly, causing frequent TLB shootdown as observed in hwpmc
supported flame graph.

Discussed with:	jeff, alfred
MFC after:	1 week

sys/kern/kern_malloc.c

@@ -120,7 +120,7 @@ static int kmemcount;
 #define KMEM_ZBASE	16
 #define KMEM_ZMASK	(KMEM_ZBASE - 1)
 
-#define KMEM_ZMAX	PAGE_SIZE
+#define KMEM_ZMAX	65536
 #define KMEM_ZSIZE	(KMEM_ZMAX >> KMEM_ZSHIFT)
 static uint8_t kmemsize[KMEM_ZSIZE + 1];
 
@@ -151,21 +151,10 @@ struct {
 	{1024, "1024", },
 	{2048, "2048", },
 	{4096, "4096", },
-#if PAGE_SIZE > 4096
 	{8192, "8192", },
-#if PAGE_SIZE > 8192
 	{16384, "16384", },
-#if PAGE_SIZE > 16384
 	{32768, "32768", },
-#if PAGE_SIZE > 32768
 	{65536, "65536", },
-#if PAGE_SIZE > 65536
-#error	"Unsupported PAGE_SIZE"
-#endif	/* 65536 */
-#endif	/* 32768 */
-#endif	/* 16384 */
-#endif	/* 8192 */
-#endif	/* 4096 */
 	{0, NULL},
 };