Fix paging #PF, simplify init_tasks

Unsure what fixed the paging #PF in init_tasks, but allocating a page
now works as expected. Originally a #PF would occur if alloc_page was
called after a certain point in init_tasks.
diff --git a/etc/platforms/x86_32/x86_32.jmk b/etc/platforms/x86_32/x86_32.jmk
index 9f8f4b0..0f60c70 100644
--- a/etc/platforms/x86_32/x86_32.jmk
+++ b/etc/platforms/x86_32/x86_32.jmk
@@ -1,4 +1,5 @@
 # -*- tcl -*-
 
 cflag -m32
+set ::asm nasm
 asmflag -felf32