objtool: Improve reloc naming

- The term "reloc" is overloaded to mean both "an instance of struct
  reloc" and "a reloc section".  Change the latter to "rsec".

- For variable names, use "sec" for regular sections and "rsec" for rela
  sections to prevent them getting mixed up.

- For struct reloc variables, use "reloc" instead of "rel" everywhere
  for consistency.

Link: https://lore.kernel.org/r/8b790e403df46f445c21003e7893b8f53b99a6f3.1685464332.git.jpoimboe@kernel.orgSigned-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

tools/objtool/include/objtool/elf.h

@@ -33,7 +33,7 @@ struct section {
 	struct rb_root_cached symbol_tree;
 	struct list_head symbol_list;
 	struct list_head reloc_list;
-	struct section *base, *reloc;
+	struct section *base, *rsec;
 	struct symbol *sym;
 	Elf_Data *data;
 	char *name;