ARM: at91: Export at91_matrix_base

at91_matrix_* macro's are used by at91_udc usb gadget driver,
which can be built as module, therefore we need to export the
variable containing matrix base address.
Signed-off-by: Joachim Eastwood <joachim.eastwood@jotron.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/mach-at91/setup.c

@@ -293,6 +293,7 @@ void __init at91_ioremap_rstc(u32 base_addr)
 }
 
 void __iomem *at91_matrix_base;
+EXPORT_SYMBOL_GPL(at91_matrix_base);
 
 void __init at91_ioremap_matrix(u32 base_addr)
 {