cputlb: Change tlb_set_dirty() arg to cpu

Change tlb_set_dirty() to accept a CPU instead of an env pointer. This
allows for removal of another CPUArchState usage from prototypes that
need to be QOMified.

Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Message-Id: <d2b1dcbe7945112989861d8ba7369449c11cc273.1441614289.git.crosthwaite.peter@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>