platform: tegra: mc: Add timeout to flush

platform: tegra: mc: Add timeout to flush

Currently tegra_mc_flush() has no timeout on silicon. However, in
some rare occassions we fail to flush and making the device hang.

This patch makes the function return -ETIMEDOUT in case we run on
silicon.

Bug 200061755

Change-Id: Id03772920ef7e1dc46bda3cb7adcf7a8ac51d5fc
Signed-off-by: Arto Merilainen <amerilainen@nvidia.com>
Reviewed-on: http://git-master/r/670699
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>