Added a TASK_CAP_LIST macro that abstracts away the primary cap list

We moved initial list of a pager's caps from ktcb to task's space
since the task is expected to trust its space.

Most references to task->cap_list had to change. Although a single
cap list only tells part of the story about the task's caps, the
TASK_CAP_LIST macro works for us to get the first private set of
caps that a task has.

include/l4/api/capability.h

@@ -20,4 +20,8 @@
 #define CAP_SHARE_CHILD			0x08	/* All that we are pager of */
 #define CAP_SHARE_SIBLING		0x10	/* All that have a common pager */
 
+/* Task's primary capability list */
+#define TASK_CAP_LIST(task)	\
+	(&((task)->space->cap_list))
+
 #endif /* __API_CAPABILITY_H__ */