Check if kernel calls is allowed (from process' call mask) added. Not yet

enforced. If a call is denied, this will be kprinted. Please report any such
errors, so that I can adjust the mask before returning errors instead of
warnings.

Wrote CMOS driver. All CMOS code from FS has been removed. Currently the
driver only supports get time calls. Set time is left out as an exercise
for the book readers ... startup scripts were updated because the CMOS driver
is needed early on. (IS got same treatment.) Don't forget to run MAKEDEV cmos
in /dev/, otherwise the driver cannot be loaded.

kernel/type.h

@@ -17,9 +17,9 @@ struct boot_image {
   char quantum;				/* quantum (tick count) */
   int priority;				/* scheduling priority */
   int stksize;				/* stack size for tasks */
-  short call_mask;			/* allowed system call traps */
-  bitchunk_t send_mask;			/* send mask protection */
-  long sys_mask;			/* system call protection */
+  short trap_mask;			/* allowed system call traps */
+  bitchunk_t ipc_to;			/* send mask protection */
+  long call_mask;			/* system call protection */
   char proc_name[P_NAME_LEN];		/* name in process table */
 };