Fixed a bug in the pack schema-related bit macros.

Details:
- Expanded the BLIS_PACK_SCHEMA_BITS value in bli_type_defs.h to
  include all six bits presently used in the pack schema bitfield of
  the info field of obj_t structs. Prior to this commit, the macro
  constant only included the lowest five bits, which excluded the
  "is or is not packed" bit. This manifested as a strange bug in
  probably many level-2 codes that invoked packing, though we only
  observed it in ger before fixing. Thanks to Devin Matthews for
  finding and reporting this bug.