usb: host: pci-quirks: Demote function header from kerneldoc to comment block

quirk_usb_handoff_xhci()'s function header is the only one across
the sourcefile which is denoted as a kerneldoc header.  Despite
no attempt to document its arguments.  Drop it down in status from
kerneldoc to a standard comment block to match the other headers
in the file.

Fixes the following W=1 kernel build warning:

 drivers/usb/host/pci-quirks.c:1145: warning: Function parameter or member 'pdev' not described in 'quirk_usb_handoff_xhci'

Cc: Mathias Nyman <mathias.nyman@intel.com>
Cc: Martin Mares <mj@ucw.cz>
Cc: aleksey_gorelov@phoenix.com
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200702144625.2533530-3-lee.jones@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/pci-quirks.c

@@ -1133,7 +1133,7 @@ void usb_disable_xhci_ports(struct pci_dev *xhci_pdev)
 }
 EXPORT_SYMBOL_GPL(usb_disable_xhci_ports);
 
-/**
+/*
  * PCI Quirks for xHCI.
  *
  * Takes care of the handoff between the Pre-OS (i.e. BIOS) and the OS.