[ARM] Feroceon: don't disable BPU on boot

On Feroceon platforms that have a branch prediction unit, bit 11 of the
cp15 control register controls the BPU.  This patch keeps the old value
of this bit instead of always clearing it.

Signed-off-by: Saeed Bishara <saeed@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>