[media] of: reserved_mem: restore old behavior when no region is defined

Change return value back to -ENODEV when no region is defined for given
device. This restores old behavior of this function, as some drivers rely
on such error code.

Fixes: 59ce4039727ef40 ("of: reserved_mem: add support for using more than
       one region for given device")

Reported-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Liviu Dudau <Liviu.Dudau@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>

drivers/of/of_reserved_mem.c

@@ -327,7 +327,7 @@ int of_reserved_mem_device_init_by_idx(struct device *dev,
 
 	target = of_parse_phandle(np, "memory-region", idx);
 	if (!target)
-		return -EINVAL;
+		return -ENODEV;
 
 	rmem = __find_rmem(target);
 	of_node_put(target);