powerpc/prom_init: Make of_workarounds static

It's not used anywhere else.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/prom_init.c

@@ -87,7 +87,7 @@
 #define OF_WORKAROUNDS	0
 #else
 #define OF_WORKAROUNDS	of_workarounds
-int of_workarounds;
+static int of_workarounds;
 #endif
 
 #define OF_WA_CLAIM	1	/* do phys/virt claim separately, then map */