asoc: tegra: i2s: Fixes for audio_clock_2x rate

audio_clock_2x parent needs to be set first before
changing the rate, else it will not work.

Bug 1019017

Signed-off-by: Nitin Pai <npai@nvidia.com>
Reviewed-on: http://git-master/r/116682
(cherry picked from commit fdc4da6d96e7be4aa2accf098de48543e745cf11)
Change-Id: I93aeb1afed8732e8a1b1cff4ab03b9a9f654804f
Reviewed-on: http://git-master/r/118250
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Bob Johnston <bjohnston@nvidia.com>
Reviewed-by: Varun Wadekar <vwadekar@nvidia.com>