Bluetooth: btintel: Zero version data before parsing TLVs

Firmware may omit optional TLVs, leaving their corresponding fields
unset in the caller-supplied struct intel_version_tlv. Since the
structure is typically stack-allocated and not cleared beforehand,
fields for which no TLV is received retain uninitialized stack
memory. This stale data can be logged via btintel_version_info_tlv()
and copied back to the caller, leaking kernel stack contents.

Clear the structure in btintel_read_version_tlv() before parsing so
that fields with no corresponding TLV are deterministically zero
instead of containing garbage.

Fixes: 57375beef71a ("Bluetooth: btintel: Add infrastructure to read controller information")
Signed-off-by: Kiran K <kiran.k@intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>