mb/{asrock,intel,purism}: Copy channel arrays separately

mb/{asrock,intel,purism}: Copy channel arrays separately

DqByteMapCh0 and DqByteMapCh1 are declared adjacently in the
FSP_M_CONFIG struct, so it is tempting to begin memcpy at the address of
the first array and overwrite both of them at once. However, FSP_M_CONFIG
is not declared with the packed attribute, so this is not guaranteed to
work and is undefined behaviour to boot. It is cleaner and less tricky
to copy them independently. The same is true for DqsMapCpu2DramCh0 and
DqsMapCpu2DramCh1, so we change those as well.

Change-Id: Ic6bb2bd5773af24329575926dbc70e0211f29051
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 136538{8,9}, 140134{1,4}
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33135
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>