Now that amd64's kernel map is 512GB (SVN rev 192216), there is no reason

to cap its buffer map at 1GB.

MFC after:	6 weeks

sys/amd64/include/param.h

@@ -136,15 +136,6 @@
 #define	VM_SWZONE_SIZE_MAX	(32 * 1024 * 1024)
 #endif
 
-/*
- * Ceiling on size of buffer cache (really only effects write queueing,
- * the VM page cache is not effected), can be changed via
- * the kern.maxbcache /boot/loader.conf variable.
- */
-#ifndef VM_BCACHE_SIZE_MAX
-#define	VM_BCACHE_SIZE_MAX	(1024 * 1024 * 1024)
-#endif
-
 /*
  * Mach derived conversion macros
  */