hte: tegra: fix 'struct of_device_id' build error

Without the extra #include, this driver produces a build failure
in some configurations.

drivers/hte/hte-tegra194-test.c:96:34: error: array type has incomplete element type 'struct of_device_id'
   96 | static const struct of_device_id tegra_hte_test_of_match[] = {

Fixes: 9a75a7cd ("hte: Add Tegra HTE test driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Dipen Patel <dipenp@nvidia.com>
Signed-off-by: Dipen Patel <dipenp@nvidia.com>