platform/x86: dell-wmi-sysman: Cleanup create_attributes_level_sysfs_files()

Cleanup create_attributes_level_sysfs_files():

1. There is no need to call sysfs_remove_file() on error, sysman_init()
will already call release_attributes_data() on failure which already does
this.

2. There is no need for the pr_debug() calls sysfs_create_file() should
never fail and if it does it will already complain about the problem
itself.

Fixes: e8a60aa7

 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Cc: Divya Bharathi <Divya_Bharathi@dell.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-8-hdegoede@redhat.com