kernel: serve GMMU static info + per-VF fault/access-counter sizes for UVM

Three fixes that clear all driver-visible errors in UVM's device create
(cuInit still fails later in UVM_REGISTER_GPU):

1. GSP_RM_CONTROL 0x20800a59 INTERNAL_GMMU_GET_STATIC_INFO (new handler):
   kgmmu.pStaticInfo->replayableFaultBufferSize feeds
   kgmmuFaultBufferReplayableAllocate (called by faultbufConstruct when UVM
   opens the device). The generic zero reply made it a 0-page allocation:
   "faultbufConstruct_IMPL: Failed to setup Replayable Fault buffer
   (status=0x51)". Report 64KB replayable / 4KB legacy, mirroring
   kgmmuSetAndGetDefaultFaultBufferSize_TU102 defaults.

2. VF-window NV_VIRTUAL_FUNCTION_PRIV_MMU_FAULT_BUFFER_SIZE(0/1)
   (BAR0+0xB83010/0xB83030, plus plain aliases) pre-filled with _VAL in
   NVC369_BUF_SIZE units (0x800=64KB, 0x80=4KB) so the local (non-RPC)
   path reads the same values the control handler reports.

3. VF-window NV_VIRTUAL_FUNCTION_PRIV_ACCESS_COUNTER_NOTIFY_BUFFER_SIZE
   (BAR0+0xB83110, plus plain alias) = 0x1000 (the value the host's
   physical TU104 reports; x32B = 128KB). uvmGetAccessCounterBufferSize_
   TU102 multiplied our zero and uvmInitializeAccessCntrBuffer failed with
   NV_ERR_NO_MEMORY at mem_desc.c:1353.

Also note (companion finding, no code change): the guest must be placed
behind a pcie-root-port; on the Q35 root bus QEMU rewrites the PCIe cap to
Root Complex Integrated Endpoint and zeroes LNKCAP/LNKCTL/DeviceCaps
(vfio_setup_pcie_cap: "On a Root Complex bus Endpoints become Root Complex
Integrated Endpoints, which changes the type and clears the LNK & LNK2
fields"), which is what made getPCIELinkRateMBps read speed 0.

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