powerpc: Fix warning when printing a resource_size_t

resource_size_t is 64 bits on PowerPC 64.

Gets rid of this warning:

arch/powerpc/kernel/pci_64.c: In function 'pcibios_map_io_space':
arch/powerpc/kernel/pci_64.c:504: warning: format '%016lx' expects type 'long unsigned int', but argument 2 has type 'resource_size_t'

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>