video: tegra: host: Fix section mismatches

nvhost context related functions were in init section, even though
they are called from non-init functions.

Bug 1022681

Change-Id: Ie85e9dd3f19873aec4153e34c7bffa19f40d37fa
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/120884
Reviewed-by: Simone Willett <swillett@nvidia.com>
Tested-by: Simone Willett <swillett@nvidia.com>