powerpc/85xx: Move ePAPR paravirt initialization earlier

At console init, when the kernel tries to flush the log buffer
the ePAPR byte-channel based console write fails silently,
losing the buffered messages.
This happens because The ePAPR para-virtualization init isn't
done early enough so that the hcall instruction to be set,
causing the byte-channel write hcall to be a nop.
To fix, change the ePAPR para-virt init to use early device
tree functions and move it in early init.

Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/arch/powerpc/include/asm/epapr_hcalls.h b/arch/powerpc/include/asm/epapr_hcalls.h
index d3d6342..86b0ac7 100644
--- a/arch/powerpc/include/asm/epapr_hcalls.h
+++ b/arch/powerpc/include/asm/epapr_hcalls.h
@@ -105,6 +105,12 @@
 extern bool epapr_paravirt_enabled;
 extern u32 epapr_hypercall_start[];
 
+#ifdef CONFIG_EPAPR_PARAVIRT
+int __init epapr_paravirt_early_init(void);
+#else
+static inline int epapr_paravirt_early_init(void) { return 0; }
+#endif
+
 /*
  * We use "uintptr_t" to define a register because it's guaranteed to be a
  * 32-bit integer on a 32-bit platform, and a 64-bit integer on a 64-bit