The data RAC is left disabled by the bootloader in some SoCs, at least in
the core it boots from. Enabling this feature increases the performance up
to +30% depending on the task.
The kernel enables the whole RAC unconditionally on BMIPS3300 CPUs. Enable
the data RAC in a similar way also for BMIPS4350.
Tested on DGND3700 v1 (BCM6368) and HG556a (BCM6358).
Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>