PCI: include io.h in pci.h so that ioremap_nocache is defined

Ingo pointed out that the m32r build was broken by pci_ioremap.  It looks like
some files include pci.h w/o including io.h.  The latter defines ioremap_* if
present, so it makes sense to include it in pci.h now that we have pci_ioremap
there.
Reported-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

include/linux/pci.h

@@ -18,6 +18,7 @@
 #define LINUX_PCI_H
 
 #include <linux/pci_regs.h>	/* The pci register defines */
+#include <linux/io.h>
 
 /*
  * The PCI interface treats multi-function devices as independent