powerpc: clean the inclusion of stringify.h

Only include linux/stringify.h is files using __stringify()

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/dcr-native.h

@@ -25,6 +25,7 @@
 #include <linux/spinlock.h>
 #include <asm/cputable.h>
 #include <asm/cpu_has_feature.h>
+#include <linux/stringify.h>
 
 typedef struct {
 	unsigned int base;