powerpc/PCI: Use for_pci_msi_entry() to access MSI device list

Use accessor for_each_pci_msi_entry() to access MSI device list, so we
could easily move msi_list from struct pci_dev into struct device
later.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Stuart Yoder <stuart.yoder@freescale.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Olof Johansson <olof@lixom.net>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Wei Yang <weiyang@linux.vnet.ibm.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Alexander Gordeev <agordeev@redhat.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Cc: Tudor Laurentiu <b10716@freescale.com>
Cc: Hongtao Jia <hongtao.jia@freescale.com>
Link: http://lkml.kernel.org/r/1436428847-8886-4-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>