ARCv2: Enable LOCKDEP

- The asm helpers for calling into irq tracer were missing

- Add calls to above helpers in low level assembly entry code for ARCv2

- irq_save() uses CLRI to disable interrupts and returns the prev interrupt
  state (in STATUS32) in a specific encoding (and not the raw value of
  STATUS32). This is usable with SETI in irq_restore(). However
  save_flags() reads the raw value of STATUS32 which doesn't pair with
  irq_save/restore() and thus needs fixing.

Signed-off-by: Evgeny Voevodin <evgeny.voevodin@intel.com>
[vgupta: updated changelog and also added some comments]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>