ARM: mx25: Print silicon revision on boot

Silicon revision is useful information to have during kernel boot.
Print the MX25 silicon revision.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Jason Liu <jason.hui@linaro.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/plat-mxc/include/mach/mx25.h b/arch/arm/plat-mxc/include/mach/mx25.h
index 087cd7a..8dcab80 100644
--- a/arch/arm/plat-mxc/include/mach/mx25.h
+++ b/arch/arm/plat-mxc/include/mach/mx25.h
@@ -104,4 +104,8 @@
 #define MX25_DMA_REQ_SSI1_RX0	28
 #define MX25_DMA_REQ_SSI1_TX0	29
 
+#ifndef __ASSEMBLY__
+extern int mx25_revision(void);
+#endif
+
 #endif /* ifndef __MACH_MX25_H__ */