Firmware on certain boards (e.g. ODROID-U3) can leave incorrect L2C prefetch
settings configured in registers leading to crashes if L2C is enabled
without overriding them. This patch introduces bindings to enable
prefetch settings to be specified from DT and necessary support in the
driver.

[mszyprow: rebased onto v3.18-rc1, added error message when prefetch related
 dt property has been provided without any value]
Signed-off-by: NTomasz Figa <t.figa@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Tested-by: NNishanth Menon <nm@ti.com>
Acked-by: NNishanth Menon <nm@ti.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>