i.MX31: Add hw-random for RNGA

This hw-random driver add support to RNGA hardware found
on some i.MX processors.

Signed-off-by: Alan Carvalho de Assis <acassis@gmail.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-mx3/Kconfig b/arch/arm/mach-mx3/Kconfig
index 0e7de94..32e4515 100644
--- a/arch/arm/mach-mx3/Kconfig
+++ b/arch/arm/mach-mx3/Kconfig
@@ -1,6 +1,7 @@
 if ARCH_MX3
 
 config ARCH_MX31
+	select ARCH_HAS_RNGA
 	bool
 
 config ARCH_MX35