of/pdt: fix section mismatch warning

Fix the following section mismatch warning - seen when building sparc32:

WARNING: vmlinux.o(.text+0x1ff9c0): Section mismatch in reference from the function kernel_tree_alloc() to the function .init.text:prom_early_alloc()
The function kernel_tree_alloc() references
the function __init prom_early_alloc().
This is often because kernel_tree_alloc lacks a __init
annotation or the annotation of prom_early_alloc is wrong.

prom_early_alloc() is annotated __init, and users of
kernel_tree_alloc() is also annotated __init.
So simply match the annoation of these to fix the warning.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>

drivers/of/pdt.c

@@ -229,7 +229,7 @@ static struct device_node * __init of_pdt_build_tree(struct device_node *parent,
 	return ret;
 }
 
-static void *kernel_tree_alloc(u64 size, u64 align)
+static void * __init kernel_tree_alloc(u64 size, u64 align)
 {
 	return prom_early_alloc(size);
 }