[ARM] 4843/1: Add GCR_CLKBPB for PXA3xx

The PXA3xx AC97 controller has an additional control bit GCR_CLKBPB
which must be used during cold reset.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>