Add explanation for DDR_CAP_AXI_ID_PORT_CHANNEL_FILTER quirk.
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20231120093317.2652866-2-xu.yang_2@nxp.comSigned-off-by: Will Deacon <will@kernel.org>