fix false disconnect due to a signal sent to the reading process

- In the current implementation, when a signal is sent to the reading process,
  read is cancelled by calling usb_ep_dequeue, which lead into calling
  acc_complete_out with ECONNRESET, but the current logic treats it as
  disconnection, which makes the device inaccessible until cable is actually
  disconnected.
- The fix calls disconnect only when ESHUTDOWN error is passed.
- If data has already arrived while trying cancelling, the data is marked
  as available, and it will be read out on the next read. This is necessary
  as USB bulk is assumed to guarantee no data loss.

Signed-off-by: keunyoung <keunyoung@google.com>
MDP: correct clock calculation logic for up-scaling scenario

Part of yscale calculation logic in mdp4_calc_req_mdp_clk
function is only applicable for downscale scenarios. The
incorrect clock calculation was unnecessarily creating
blt mode requirement even for upscale scenarios.

Change-Id: I036be2ceb2f59fb159885b2d15b208706808198b
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>