[POWERPC] Add missing native dcr dcr_ind_lock spinlock

The include/asm-powerpc/dcr-native.h declares extern spinlock_t dcr_ind_lock;
but it's actually isn't defined. This patch adds a missing dcr_ind_lock.
Signed-off-by: NValentine Barshak <vbarshak@ru.mvista.com>
Signed-off-by: NJosh Boyer <jwboyer@linux.vnet.ibm.com>

arch/powerpc/sysdev/dcr.c

@@ -137,5 +137,6 @@ void dcr_unmap(dcr_host_t host, unsigned int dcr_c)
 	h.token = NULL;
 }
 EXPORT_SYMBOL_GPL(dcr_unmap);
-
+#else	/* defined(CONFIG_PPC_DCR_NATIVE) */
+DEFINE_SPINLOCK(dcr_ind_lock);
 #endif	/* !defined(CONFIG_PPC_DCR_NATIVE) */