games/NXDoom: drop the assignments left over from dehacked

Six statements assign a variable to itself, which clang rejects:

  src/doom/f_finale.c:637:16: error: explicitly assigning value of
  variable of type 'const char *' to itself [-Werror,-Wself-assign]
    637 |       lumpname = (lumpname);

Chocolate DOOM wraps those strings in DEH_String() so that a dehacked
patch can substitute them. The port has no dehacked support, and the
macro went away with it, leaving the parentheses behind. Two comments
that only described the substitution go as well.

Nothing changes at run time. GCC does not warn about this, so the
configurations built so far never noticed; the ones built with clang
do, and they fail because the CI treats warnings as errors.

Signed-off-by: Jorge Guzman <jorge.gzm@gmail.com>

games/NXDoom/src/doom/f_finale.c

@@ -634,8 +634,6 @@ static void f_art_screen_drawer(void)
           return;
         }
 
-      lumpname = (lumpname);
-
       v_draw_patch(0, 0, w_cache_lump_name(lumpname, PU_CACHE));
     }
 }
@@ -688,11 +686,6 @@ void f_start_finale(void)
         }
     }
 
-  /* Do dehacked substitutions of strings */
-
-  finaletext = (finaletext);
-  finaleflat = (finaleflat);
-
   finalestage = F_STAGE_TEXT;
   finalecount = 0;
 }

games/NXDoom/src/doom/g_game.c

@@ -442,8 +442,6 @@ static void g_do_load_level(void)
           skytexturename = "SKY3";
         }
 
-      skytexturename = (skytexturename);
-
       skytexture = r_texture_num_for_name(skytexturename);
     }
 
@@ -2285,7 +2283,6 @@ void g_init_new(skill_t skill, int episode, int map)
           break;
         }
 
-      skytexturename = (skytexturename);
       skytexture = r_texture_num_for_name(skytexturename);
     }
 

games/NXDoom/src/doom/hu_stuff.c

@@ -381,9 +381,6 @@ void hu_start(void)
       s = HU_TITLE_CHEX;
     }
 
-  /* dehacked substitution to get modified level name */
-
-  s = (s);
   while (*s)
     {
       hu_lib_add_char_to_text_line(&w_title, *(s++));