video: tegra: host: new syncpoint max interface

Add the NVHOST_IOCTL_CTRL_SYNCPT_READ_MAX ioctl for reading max value
of a syncpoint.

Bug 1039058

Change-Id: I61c348c3007a4fb919fbe48993907d46f38c5fa8
Signed-off-by: Michal Pecio <mpecio@nvidia.com>
Reviewed-on: http://git-master/r/132387
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>