serial: lpuart: Proper device identification

Identify and distinguish between platform device type of MX7ULP
and LS1021A.

This is a fix to commit 7edf5c45("serial: lpuart: add i.MX7ULP
support").

Signed-off-by: Sriram Dash <sriram.dash@nxp.com>
Acked-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
1 file changed