powerpc/4xx/pci: Add __init annotations for *init_port_hw() functions.

The various port_init_hw methods of ppc4xx_pciex_hwops should have been
marked __init and when I added ppc4xx_pciex_port_reset_sdr(), which is
__init.  This added many section mismatch warnings like:

WARNING: arch/powerpc/sysdev/built-in.o(.text+0x5c68): Section mismatch in reference from the function ppc440spe_pciex_init_port_hw() to the function .init.text:ppc4xx_pciex_port_reset_sdr()
The function ppc440spe_pciex_init_port_hw() references
the function __init ppc4xx_pciex_port_reset_sdr().
This is often because ppc440spe_pciex_init_port_hw lacks a __init
annotation or the annotation of ppc4xx_pciex_port_reset_sdr is wrong.

Trivial patch to silence those warnings.

Reported-By: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>

Yours Tony
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>