kernel: backport MIPS's ioremap_cache from 4.5

It's needed by (updated) bcm47xxsflash driver.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

target/linux/generic/patches-4.4/097-MIPS-io.h-Define-ioremap_cache.patch

@@ -0,0 +1,29 @@
+From a68f376844605399cbd28b662d5ed213639f46f7 Mon Sep 17 00:00:00 2001
+From: "Maciej W. Rozycki" <macro@imgtec.com>
+Date: Sat, 9 Jan 2016 02:05:31 +0000
+Subject: [PATCH] MIPS: io.h: Define `ioremap_cache'
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
+Cc: Brian Norris <computersforpeace@gmail.com>
+Cc: Rafał Miłecki <zajec5@gmail.com>
+Cc: linux-mips@linux-mips.org
+Cc: linux-kernel@vger.kernel.org
+Patchwork: https://patchwork.linux-mips.org/patch/12040/
+Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
+---
+ arch/mips/include/asm/io.h | 1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/arch/mips/include/asm/io.h
++++ b/arch/mips/include/asm/io.h
+@@ -275,6 +275,7 @@ static inline void __iomem * __ioremap_m
+  */
+ #define ioremap_cachable(offset, size)					\
+ 	__ioremap_mode((offset), (size), _page_cachable_default)
++#define ioremap_cache ioremap_cachable
+ 
+ /*
+  * These two are MIPS specific ioremap variant.	 ioremap_cacheable_cow