generic: fix disable common USB quirks patch

generic: fix disable common USB quirks patch

Remove modifications for codes guarded by CONFIG_USB_PCI_AMD.
This kernel symbol is only visible on desktop level platform,
e.g. x86. They are not sensitive to firmware image size. This
patch also fixes function redefinition build errors:

drivers/usb/host/pci-quirks.c:621:6: error: redefinition of 'usb_asmedia_modifyflowcontrol'
  621 | void usb_asmedia_modifyflowcontrol(struct pci_dev *pdev)
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from drivers/usb/host/pci-quirks.c:22:
drivers/usb/host/pci-quirks.h:49:20: note: previous definition of 'usb_asmedia_modifyflowcontrol' with type 'void(struct pci_dev *)'
   49 | static inline void usb_asmedia_modifyflowcontrol(struct pci_dev *pdev) {}
      |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: be6753dda00c ("generic: 6.12: manually rebuild pending patches")
Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/18637
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>