add a hit that you can enable this by default if you want... necessary

if you want the keyboard break to work early in boot..

MFC after:	1 week

sys/boot/forth/loader.conf

@@ -134,6 +134,7 @@ module_path="/boot/modules"	# Set the module search path
 #vfs.root.mountfrom=""		# Specify root partition in a way the
 				# kernel understands
 #vm.kmem_size=""		# Sets the size of kernel memory (bytes)
+#debug.kdb.break_to_debugger="0" # Allow console to break into debugger.
 #debug.ktr.cpumask="0xf"	# Bitmask of CPUs to enable KTR on
 #debug.ktr.mask="0x1200"	# Bitmask of KTR events to enable
 #debug.ktr.verbose="1"		# Enable console dump of KTR events