bus: imx-aipstz: set default value for opacr registers

bus: imx-aipstz: set default value for opacr registers

The sdma script app_2_mcu needs the permission to access the peripheral
devices:

1) SDMA2 transactions are set to user-mode in this particular case.
2) This type of script doesn't use the peripheral interface (connected
directly to SPBA), but it uses the peripheral DMA interface, then the
SDMA2-issued transactions are subjected to AIPSTZ5's security-related
checks.

So need to clear the Supervisor Protect bit of SPBA2, otherwise the sdma
script can't work. As the imx-aipstz is a common driver for all aips bus,
so set default value (zero) for all opacr registers.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>