ARM: imx: set cache line size to 64 bytes for i.MX5

The core of i.MX5 series is cortex-A8, its cache line size is 64 bytes
instead of 32 bytes. Refer to the OMAP3's selection, we choose 64
bytes for i.MX5, this can increase a little bit performance when
perform cache operations.
Signed-off-by: Jason Wang <jason77.wang@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/plat-mxc/Kconfig

@@ -43,6 +43,7 @@ config ARCH_MXC91231
 config ARCH_MX5
 	bool "MX5-based"
 	select CPU_V7
+	select ARM_L1_CACHE_SHIFT_6
 	help
 	  This enables support for systems based on the Freescale i.MX51 family