staging: unisys: don't care about debugfs errors

A caller should never care about a debugfs error return value, and it
should never abort its normal operation if something "odd" goes on.  Fix
up the unisys init code to not care if the root debugfs directory for
the subsystem is created or not, as no place it is used will matter.

Cc: David Kershner <david.kershner@unisys.com>
Cc: Tim Sell <Timothy.Sell@unisys.com>
Cc: Sameer Wadgaonkar <sameer.wadgaonkar@unisys.com>
Cc: David Binder <david.binder@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>