LF-3763 arm64: dts: SOF: Use newly created names for default topologies

commit f182c7aeb81b77801e1992b7a972545734b34ee7 from
git://source.codeaurora.org/external/qoriq/qoriq-components/linux



Because i.MX8QXP/i.MX8QM are similar w.r.t audio peripherals
configuration we currently use the following naming for
topologies sof-imx8qxp-<codec>.tplg.

Which is weird to see for i.MX8QM.

In order to make naming more generic use imx8 instead of imx8qxp/imx8qm.

Reviwed-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Meng Li <Meng.Li@windriver.com>