sparc/PCI: Add mem64 resource parsing for root bus

sparc/PCI: Add mem64 resource parsing for root bus

Found "no compatible bridge window" warning in boot log from T5-8.

pci 0000:00:01.0: can't claim BAR 15 [mem 0x100000000-0x4afffffff pref]: no compatible bridge window

That resource is above 4G, but does not get offset correctly as
root bus only report io and mem32.

pci_sun4v f02dbcfc: PCI host bridge to bus 0000:00
pci_bus 0000:00: root bus resource [io  0x804000000000-0x80400fffffff] (bus address [0x0000-0xfffffff])
pci_bus 0000:00: root bus resource [mem 0x800000000000-0x80007effffff] (bus address [0x00000000-0x7effffff])
pci_bus 0000:00: root bus resource [bus 00-77]

Add mem64 handling in pci_common for sparc, so we can have 64bit resource
registered for root bus at first.

After patch, will have:
pci_sun4v f02dbcfc: PCI host bridge to bus 0000:00
pci_bus 0000:00: root bus resource [io  0x804000000000-0x80400fffffff] (bus address [0x0000-0xfffffff])
pci_bus 0000:00: root bus resource [mem 0x800000000000-0x80007effffff] (bus address [0x00000000-0x7effffff])
pci_bus 0000:00: root bus resource [mem 0x800100000000-0x8007ffffffff] (bus address [0x100000000-0x7ffffffff])
pci_bus 0000:00: root bus resource [bus 00-77]

Fixes: commit d63e2e1f3df9 ("sparc/PCI: Clip bridge windows to fit in upstream windows")
Link: http://lkml.kernel.org/r/CAE9FiQU1gJY1LYrxs+ma5LCTEEe4xmtjRG0aXJ9K_Tsu+m9Wuw@mail.gmail.com
Reported-by: David Ahern <david.ahern@oracle.com>
Tested-by: David Ahern <david.ahern@oracle.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: <stable@vger.kernel.org> #3.19
(cherry picked from commit cd252f7298ec848ec23745938a84259999bdbe25)
(cherry picked from commit 4be8ce4e960931c18d3d5098bb9e2c6e0509b80e)