SecurityPkg: TcgStorageOpalLib: Initialize SupportedAttributes parameter.

SecurityPkg: TcgStorageOpalLib: Initialize SupportedAttributes parameter.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3408

The value of SupportedAttributes in OpalGetSupportedAttributesInfo ()
is left undetermined, if the caller doesn't initialize it.
Initialize it in the function entry.

Signed-off-by: Scottie Kuo <scottie.kuo@intel.com>
Cc: Qi Zhang <qi1.zhang@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Maggie Chu <maggie.chu@intel.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
Acked-by: Jian J Wang <jian.j.wang@intel.com>