nios2: Fix ioremap

Commit 5ace77e ("nios2: remove __ioremap") removed the following code,
with the argument that cacheflag is always 0 and the expression would
therefore always be false.

	if (IS_MAPPABLE_UNCACHEABLE(phys_addr) &&
	    IS_MAPPABLE_UNCACHEABLE(last_addr) &&
	    !(cacheflag & _PAGE_CACHED))
		return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr);

This did not take the "!" in the expression into account. Result is that
nios2 images no longer boot. Restoring the removed code fixes the problem.

Fixes: 5ace77e ("nios2: remove __ioremap")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>

arch/nios2/mm/ioremap.c

@@ -138,6 +138,14 @@ void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
 				return NULL;
 	}
 
+	/*
+	 * Map uncached objects in the low part of address space to
+	 * CONFIG_NIOS2_IO_REGION_BASE
+	 */
+	if (IS_MAPPABLE_UNCACHEABLE(phys_addr) &&
+	    IS_MAPPABLE_UNCACHEABLE(last_addr))
+		return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr);
+
 	/* Mappings have to be page-aligned */
 	offset = phys_addr & ~PAGE_MASK;
 	phys_addr &= PAGE_MASK;