grub/xhci: Add xHCI non-root-hub fixes from Nitrokey

See:
https://github.com/Nitrokey/nethsm-grub/commits/nethsm-z790?since=2025-01-13&until=2025-01-13

And more generally, see branch:
https://github.com/Nitrokey/nethsm-grub/commits/nethsm-z790

This brings in a few minor fixes, and also a not-so-minor fix:
Add TT (transaction translation) handling for non-SuperSpeed
devices in xhci.c

More generally, this patchset will improve non-root hub support
in the xHCI code. There is also a patch to work around a quirk
on the MSI Z790-P mainboard, which I'm planning to add to Libreboot
at a later date.

Signed-off-by: Leah Rowe <leah@libreboot.org>

config/grub/xhci/patches/0021-xHCI-also-accept-SBRN-0x31-and-0x32.patch

@@ -0,0 +1,26 @@
+From 3fa33c091866b13c452b7a39ecee291e5901ff22 Mon Sep 17 00:00:00 2001
+From: Sven Anderson <sven@anderson.de>
+Date: Sat, 28 May 2022 21:39:23 +0200
+Subject: [PATCH 21/26] xHCI: also accept SBRN 0x31 and 0x32
+
+Signed-off-by: Sven Anderson <sven@anderson.de>
+---
+ grub-core/bus/usb/xhci-pci.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/grub-core/bus/usb/xhci-pci.c b/grub-core/bus/usb/xhci-pci.c
+index a5bd3c97d..cde21f57a 100644
+--- a/grub-core/bus/usb/xhci-pci.c
++++ b/grub-core/bus/usb/xhci-pci.c
+@@ -76,7 +76,7 @@ grub_xhci_pci_iter (grub_pci_device_t dev, grub_pci_id_t pciid,
+       /* Check Serial Bus Release Number */
+       addr = grub_pci_make_address (dev, GRUB_XHCI_PCI_SBRN_REG);
+       release = grub_pci_read_byte (addr);
+-      if (release != 0x30)
++      if (release != 0x30 && release != 0x31 &&release != 0x32)
+ 	{
+ 	  grub_dprintf ("xhci", "XHCI grub_xhci_pci_iter: Wrong SBRN: %0x\n",
+ 			release);
+-- 
+2.39.5
+