soc: nxp: imx: imx8m: Align resource table to 64bit for i.MX 8M

Running samples/subsys/ipc/openamp_rsc_table with some adjustments
sometimes results in linux kernel panics.

After experimenting it appears to be hit or miss depending on the
resource table alignment.
Explicitly aligning to 64bit (the native width), no more kernel panics
were seen.

Signed-off-by: Pieter De Gendt <pieter.degendt@basalte.be>