Fix wrong variable value in icon_atmosphere_real-from-ideal_01.namelist

namelists/icon_atmosphere_real-from-ideal_01.namelist

 &run_nml
-    ltestcase                   = .false.
-    dtime                       =  300
-    output                      = 'nml'
+    ltestcase                   = .TRUE.        ! idealized testcase runs
+    dtime                       = 300           ! time step of 300 seconds
+    output                      = 'nml'         ! use output nameslists
     msg_level                   = 15
     num_lev                     = 31
     lvert_nest                  = .false.
@@ -42,6 +42,10 @@
     dt_checkpoint = '%checkpoint_time%'
 /
 
+&parallel_nml
+    nproma                      = 16
+/
+
 ! the following two output files are used to initialize the next run
 &output_nml
     file_interval               = 'PT3600S'