armv8/fsl-lsch2: make the workaround for PIN MUX erratum A010539 robust

Mask HRESET_B after cleared the the RCW_SRC, because in the workaround
we override the RCW_SRC and if HRESET_B is issued after the override
then SoC cannot find valid RCW as the RCW_SRC was overwritten and
result in hang. So we need to mask HRESET_B in case user asserts it,
and the PORESET_B should be asserted which leads to resampling of
cfg_rcw_src pins and loading of correct RCW_SRC.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>