ANDROID: mmc: sdio: Disable retuning in sdio_reset_comm()

Since sdio_reset_comm() re-initializes the SDIO card, disable retuning
before idling and shutting down the card.  Tuning will be re-enabled (if
necessary) in mmc_sdio_init_card().

BUG=chrome-os-partner:46444
TEST=With CL:311815, toggle WiFi on/off on Smaug and observe that the
WiFi card comes back up and is able to tune successfully.

Change-Id: Ib4a5cfd4d75fc9e3ed7bb3f1e2ffd30de16c5d28
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/311797


Reviewed-by: Derek Basehore <dbasehore@chromium.org>

[briannorris: brought from Chromium kernel in 3.18 -> 4.4 rebase]

Signed-off-by: Brian Norris <briannorris@google.com>