[PATCH] Call populate_rootfs later in boot

[PATCH] Call populate_rootfs later in boot

populate_rootfs() is called rather early - before we've called init_idle().

But populate_rootfs() does file I/O, which involves calls to cond_resched(),
and downing of semaphores, etc.  If it scheules, the scheduler emits
scheduling-while-atomic warnings and sometimes oopses.

So run populate_rootfs() later, after the scheduler is all set up.