tgsi: Fix return of uninitialized memory in tgsi_*_instruction_memory

tgsi: Fix return of uninitialized memory in tgsi_*_instruction_memory

tgsi_default_instruction_memory / tgsi_build_instruction_memory were
returning uninitialized memory for tgsi_instruction_memory.Texture and
tgsi_instruction_memory.Format. Note 0 means not set, and thus is a
correct default initializer for these.

Fixes: 3243b6fc97 ("tgsi: add Texture and Format to tgsi_instruction_memory")
Cc: Nicolai Hähnle <nicolai.haehnle@amd.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>