powerpc/powernv: Include asm/powernv.h from the local powernv.h

The asm/powernv.h header provides prototypes for functions which need to be
called by non-powernv platform code. Also include it in the powernv.h
that's local to the platform directory to squash some warnings about
non-static functions missing prototypes.

Also include powernv.h since from opal-memcons.c since it has the
prototypes for the memcons wrangling functions which are used for the opal
and ultravisor msglog.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-3-oohall@gmail.com

arch/powerpc/platforms/powernv/opal-msglog.c

@@ -12,6 +12,8 @@
 #include <linux/types.h>
 #include <asm/barrier.h>
 
+#include "powernv.h"
+
 /* OPAL in-memory console. Defined in OPAL source at core/console.c */
 struct memcons {
 	__be64 magic;

arch/powerpc/platforms/powernv/powernv.h

@@ -2,6 +2,13 @@
 #ifndef _POWERNV_H
 #define _POWERNV_H
 
+/*
+ * There's various hacks scattered throughout the generic powerpc arch code
+ * that needs to call into powernv platform stuff. The prototypes for those
+ * functions are in asm/powernv.h
+ */
+#include <asm/powernv.h>
+
 #ifdef CONFIG_SMP
 extern void pnv_smp_init(void);
 #else