intr_disabled() tests removed

- we don't need to test this in kernel as we always have interrupts
  disabled

- if interrupts are enabled in kernel, it is only at very carefully
  chosen places. There are no such places now.

kernel/vm.h

@@ -10,7 +10,6 @@
 #define FIXLINMSG(prp) { prp->p_delivermsg_lin = umap_local(prp, D, prp->p_delivermsg_vir, sizeof(message)); }
 
 #define PHYS_COPY_CATCH(src, dst, size, a) {	\
-	vmassert(intr_disabled());		\
 	catch_pagefaults++;			\
 	a = phys_copy(src, dst, size);		\
 	catch_pagefaults--;			\