usb: xhci: remove false xhci_giveback_urb_in_irq() header comment

usb: xhci: remove false xhci_giveback_urb_in_irq() header comment

The function doesn't releases and re-acquires the lock, this was removed
in commit 36dc01657b49 ("usb: host: xhci: Support running urb giveback in
tasklet context")

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240626124835.1023046-17-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>