uprobes: Copy_insn() shouldn't depend on mm/vma/vaddr

uprobes: Copy_insn() shouldn't depend on mm/vma/vaddr

1. copy_insn() doesn't need "addr", it can use uprobe->offset.
   Remove this argument.

2. Change copy_insn/__copy_insn to accept "struct file*" instead
   of vma.

copy_insn() is called only once and mm/vma/vaddr are random, it
shouldn't depend on them.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154342.GA9598@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>