Default CO2 is not right in GIAF configuration

[mnlevy1981]

In /glade/work/mlevy/codes/CESM/cesm2_3_beta16+mom6_marbl/long_runs/GIAF_comparisons/g.e23b16.TL319_t232.GIAFMARBL.001, @klindsay28 noted

I spot-checked some fields with ncview and they look reasonable, with one exception.
It looks like ATM_CO2 is 367. So we won't be able to look at drift in DIC.

Want to make sure we are setting this correctly in all cases

[mnlevy1981]

This requires a change in CMEPS:

diff --git a/cime_config/config_component_cesm.xml b/cime_config/config_component_cesm.xml
index dbf3b11e..7a7db452 100644
--- a/cime_config/config_component_cesm.xml
+++ b/cime_config/config_component_cesm.xml
@@ -109,6 +109,8 @@
       <value compset="_DATM">none</value>
       <value compset="_DATM%CPLHIST.+POP\d">CO2A</value>
       <value compset="_DATM%CPLHIST.+BLOM%ECO">CO2A</value>
+      <value compset="^OMIP_DATM%IAF.*_MOM6%[^_]*MARBL">CO2A</value>
+      <value compset="^OMIP_DATM%JRA.*_MOM6%[^_]*MARBL">CO2A</value>
       <value compset="^OMIP_DATM%IAF.*_POP2%[^_]*ECO">CO2A</value>
       <value compset="^OMIP_DATM%JRA.*_POP2%[^_]*ECO">CO2A</value>
       <value compset="HIST.*_DATM.*_CLM">CO2A</value>
@@ -496,6 +498,7 @@
     <default_value>284.7</default_value>
     <values match="last">
       <value compset="^2000">367.0</value>
+      <value compset="DATM.*_MOM6%[^_]*MARBL">284.317</value>
       <value compset="DATM.*_POP2%[^_]*ECO">284.317</value>
       <value compset="DATM.*_POP2%[^_]*ECOCESM20">284.7</value>
     </values>