ARM: reintroduce ioremap_cached() for creating cached I/O mappings

The original ARM-only ioremap flavor 'ioremap_cached' has been renamed
to 'ioremap_cache' to align with other architectures, and subsequently
abused in generic code to map things like firmware tables in memory.
For that reason, there is currently an effort underway to deprecate
ioremap_cache, whose semantics are poorly defined, and which is typed
with an __iomem annotation that is inappropriate for mappings of ordinary
memory.

However, original users of ioremap_cached() used it in a context where
the I/O connotation is appropriate, and replacing those instances with
memremap() does not make sense. So let's revive ioremap_cached(), so
that we can change back those original users before we drop ioremap_cache
entirely in favor of memremap.

Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

arch/arm/mm/nommu.c

@@ -367,11 +367,15 @@ void __iomem *ioremap(resource_size_t res_cookie, size_t size)
 EXPORT_SYMBOL(ioremap);
 
 void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
+	__alias(ioremap_cached);
+
+void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size)
 {
 	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
 				    __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_cache);
+EXPORT_SYMBOL(ioremap_cached);
 
 void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
 {