Configure the data and tag latency for the L2 cache. This improves the
system performance.

This configuration is taken from Freescale's kernel patch

"ENGR00153601 [MX6]Adjust L2 cache parameter" [1]

which does

writel(0x132, IO_ADDRESS(L2_BASE_ADDR + L2X0_TAG_LATENCY_CTRL));
writel(0x132, IO_ADDRESS(L2_BASE_ADDR + L2X0_DATA_LATENCY_CTRL));

In this patch we are doing the same via the device tree.
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

[1] http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/commit/arch/arm/mach-mx6/mm.c?h=imx_3.0.35_12.09.01&id=814656410b40c67a10b25300e51b0477b2bb96d1