tile: provide default ioremap declaration

Add a default ioremap function which was not provided in all
circumstances.  (Only when CONFIG_PCI and CONFIG_TILEGX was set).

I have designs to use them in scatterlist.c where they'd likely never be
called with this architecture, but it is needed to compile.  Thus, if
the function is ever hit it returns NULL.

Link: http://lkml.kernel.org/r/1495726904-27380-1-git-send-email-logang@deltatee.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Stephen Bates <sbates@raithlin.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/tile/mm/pgtable.c

@@ -503,6 +503,17 @@ void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size,
 }
 EXPORT_SYMBOL(ioremap_prot);
 
+#if !defined(CONFIG_PCI) || !defined(CONFIG_TILEGX)
+/* ioremap is conditionally declared in pci_gx.c */
+
+void __iomem *ioremap(resource_size_t phys_addr, unsigned long size)
+{
+	return NULL;
+}
+EXPORT_SYMBOL(ioremap);
+
+#endif
+
 /* Unmap an MMIO VA mapping. */
 void iounmap(volatile void __iomem *addr_in)
 {