devres: introduce API "devm_kmemdup

Introduce devm_kmemdup, which uses resource managed kmalloc.
There are several request from maintainers to add this instead
of using kmemdup.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/include/linux/device.h b/include/linux/device.h
index d1d1c05..ab87158 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -623,6 +623,8 @@
 }
 extern void devm_kfree(struct device *dev, void *p);
 extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp);
+extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
+			  gfp_t gfp);
 
 void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
 void __iomem *devm_request_and_ioremap(struct device *dev,