[MIPS] BCM1480: Export zbbus_mhz.

Symbol is required by the ZBus profiler.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/sibyte/bcm1480/setup.c b/arch/mips/sibyte/bcm1480/setup.c
index bb28f28..f2eefbe 100644
--- a/arch/mips/sibyte/bcm1480/setup.c
+++ b/arch/mips/sibyte/bcm1480/setup.c
@@ -35,6 +35,7 @@
 EXPORT_SYMBOL(soc_type);
 unsigned int periph_rev;
 unsigned int zbbus_mhz;
+EXPORT_SYMBOL(zbbus_mhz);
 
 static unsigned int part_type;