platform/x86: intel_ips: remove unnecessary checks in ips_debugfs_init

As Greg KH explained in:
https://lkml.org/lkml/2015/8/15/114



There no need to check the return value of debugfs_create_file() and
debugfs_create_dir().

This also fix static code checker warnings:

drivers/platform/x86/intel_ips.c:1314
 ips_debugfs_init() warn: passing zero to 'PTR_ERR'
drivers/platform/x86/intel_ips.c:1328
 ips_debugfs_init() warn: passing zero to 'PTR_ERR'

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>