video: tegra: dp: Update dpaux_write interface

video: tegra: dp: Update dpaux_write interface

The function tegra_dc_dpaux_read() expects read
data length to be exact the number of bytes to be read,
while tegra_dc_dpaux_write() expects write data length
to be N-1 bytes.
This change fixes this discrepancy and changes dpaux_write
to expect the exact number of bytes as well.

Bug 1315461

Change-Id: Ica490dd3fd721620912b22776d855063d8028e30
Signed-off-by: Daniel Solomon <daniels@nvidia.com>
Reviewed-on: http://git-master/r/376792
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Animesh Kishore <ankishore@nvidia.com>
Reviewed-by: Chao Xu <cxu@nvidia.com>