Clean up to kernel code, Added `used' field to capabilities

With the addition of used field, capability structure can be
used for resource accounting over the capability.

src/api/capability.c

@@ -14,7 +14,7 @@
 #include INC_API(syscall.h)
 
 
-int task_read_capabilities(void *userbuf)
+int read_task_capabilities(void *userbuf)
 {
 	int copy_size, copy_offset = 0;
 	struct capability *cap;
@@ -69,7 +69,7 @@ int sys_capability_control(unsigned int req, unsigned int flags, void *userbuf)
 
 	/* Return all capabilities as an array of capabilities */
 	case CAP_CONTROL_READ_CAPS:
-		err = task_read_capabilities(userbuf);
+		err = read_task_capabilities(userbuf);
 		break;
 
 	default:

src/api/space.c

@@ -9,13 +9,6 @@
 #include <l4/api/errno.h>
 #include <l4/api/space.h>
 
-/* NOTE:
- * For lazy mm switching, a list of newly created mappings that are common to
- * all tasks (e.g. any mapping done in the kernel) can be kept here so that when
- * a new task is scheduled, the same mappings are copied to its page tables as
- * well. struct link new_mappings;
- */
-
 int sys_map(unsigned long phys, unsigned long virt, unsigned long npages,
 	    unsigned long flags, unsigned int tid)
 {