drm/tegra: replace idr_init() by idr_init_base()

idr_init() uses base 0 which is an invalid identifier for this driver.
The new function idr_init_base allows IDR to set the ID lookup from
base 1. This avoids all lookups that otherwise starts from 0 since
0 is always unused.

References: commit 6ce711f2 ("idr: Make 1-based IDRs more efficient")

Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>