lib/iomap_copy.c: add __ioread32_copy()

Some drivers need to read data out of iomem areas 32-bits at a time.
Add an API to do this.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Cc: <zajec5@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/io.h b/include/linux/io.h
index fffd88d..32403b5 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -29,6 +29,7 @@
 struct resource;
 
 __visible void __iowrite32_copy(void __iomem *to, const void *from, size_t count);
+void __ioread32_copy(void *to, const void __iomem *from, size_t count);
 void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
 
 #ifdef CONFIG_MMU