[PATCH] powerpc: Fix !SMP build of rtas.c

arch/powerpc/kernel/rtas.c is getting hvcall.h via spinlock.h, but when we're
building for UP we don't include spinlock.h.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/rtas.c

@@ -22,6 +22,7 @@
 
 #include <asm/prom.h>
 #include <asm/rtas.h>
+#include <asm/hvcall.h>
 #include <asm/semaphore.h>
 #include <asm/machdep.h>
 #include <asm/page.h>