soc/tegra: cbb: Drop unnecessary debugfs error handling

soc/tegra: cbb: Drop unnecessary debugfs error handling

Kernel coding style expects all drivers to ignore debugfs errors.
Partially because it is purely for debugging, not for important user
interfaces.  Simplify the code by dropping unnecessary probe failuring
and error message on debugfs failures, which also fixes incorrect usage
IS_ERR_OR_NULL() and Smatch warning:

  drivers/soc/tegra/cbb/tegra-cbb.c:80 tegra_cbb_err_debugfs_init() warn: passing zero to 'PTR_ERR'

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250104141958.115911-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Thierry Reding <treding@nvidia.com>