PCI/TSM: Add 'dsm' and 'bound' attributes for dependent functions

PCI/TSM: Add 'dsm' and 'bound' attributes for dependent functions

PCI/TSM sysfs for physical function 0 devices, i.e. the "DSM" (Device
Security Manager), contains the 'connect' and 'disconnect' attributes.
After a successful 'connect' operation the DSM, its dependent functions
(SR-IOV virtual functions, non-zero multi-functions, or downstream
endpoints of a switch DSM) are candidates for being transitioned into a
TDISP (TEE Device Interface Security Protocol) operational state, via
pci_tsm_bind(). At present sysfs is blind to which devices are capable of
TDISP operation and it is ambiguous which functions are serviced by which
DSMs.

Add a 'dsm' attribute to identify a function's DSM device, and add a
'bound' attribute to identify when a function has entered a TDISP
operational state.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Samuel Ortiz <sameo@rivosinc.com>
Cc: Alexey Kardashevskiy <aik@amd.com>
Cc: Xu Yilun <yilun.xu@linux.intel.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20251113021446.436830-9-dan.j.williams@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>