Fix modpost warning in serial driver

This is triggered if PCI && !HOTPLUG.

  MODPOST vmlinux.o
WARNING: vmlinux.o(.data+0xc910): Section mismatch: reference to .init.text:pci_ite887x_init (between 'pci_serial_quirks' and 'serial_pci_tbl')

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>