generic: add ioremap_wc() interface wrapper

x86 has ioremap_wc for wc remap. Also introduce a generic ioremap_wc
aliased to ioremap_uc so that drivers can use this interface transparently.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/asm-generic/iomap.h

@@ -60,6 +60,10 @@ extern void iowrite32_rep(void __iomem *port, const void *buf, unsigned long cou
 extern void __iomem *ioport_map(unsigned long port, unsigned int nr);
 extern void ioport_unmap(void __iomem *);
 
+#ifndef ARCH_HAS_IOREMAP_WC
+#define ioremap_wc ioremap_nocache
+#endif
+
 /* Create a virtual mapping cookie for a PCI BAR (memory or IO) */
 struct pci_dev;
 extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);