Clean up kernel/proc, remove devs_spinlock, remove PROC_DIE() macro

kernel/proc/proc.h

@@ -61,7 +61,6 @@ typedef struct Proc {
   SpinLock pipes_spinlock;
 
   Dev *devs[PROC_DEVHANDLES_MAX];
-  SpinLock devs_spinlock;
 
   struct {
     ProcArg *list;
@@ -88,13 +87,6 @@ void proc_sched(void *cpustate);
 void proc_killself(void);
 void proc_kill(Proc *proc);
 
-#define PROC_DIE() \
-  do { \
-    proc_killself(); \
-    for(;;); \
-  } while(0)
-
-
 #define PROC_ARG(proc, str) \
   do { \
     ProcArg *__arg = dlmalloc(sizeof(*__arg)); \