mtip32xx: Remove redundant null pointer checks in mtip_hw_debugfs_init()

mtip32xx: Remove redundant null pointer checks in mtip_hw_debugfs_init()

Since the debugfs_create_dir() never returns a null pointer, checking
the return value for a null pointer is redundant. Since
debugfs_create_file() can deal with a ERR_PTR() style pointer, drop
the check.  Since mtip_hw_debugfs_init does not pay attention to the
return value, its return type can be changed to void.

Signed-off-by: Li Zetao <lizetao1@huawei.com>
Link: https://lore.kernel.org/r/20240907034046.3595268-1-lizetao1@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>