objtool: Reorganize cmdline options

Split the existing options into two groups: actions, which actually do
something; and options, which modify the actions in some way.

Also there's no need to have short flags for all the non-action options.
Reserve short flags for the more important actions.

While at it:

- change a few of the short flags to be more intuitive

- make option descriptions more consistently descriptive

- sort options in the source like they are when printed

- move options to a global struct

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/9dcaa752f83aca24b1b21f0b0eeb28a0c181c0b0.1650300597.git.jpoimboe@redhat.com

tools/objtool/objtool.c

@@ -118,7 +118,7 @@ struct objtool_file *objtool_open_read(const char *_objname)
 	if (!file.elf)
 		return NULL;
 
-	if (backup && !objtool_create_backup(objname)) {
+	if (opts.backup && !objtool_create_backup(objname)) {
 		WARN("can't create backup file");
 		return NULL;
 	}
@@ -129,7 +129,7 @@ struct objtool_file *objtool_open_read(const char *_objname)
 	INIT_LIST_HEAD(&file.static_call_list);
 	INIT_LIST_HEAD(&file.mcount_loc_list);
 	INIT_LIST_HEAD(&file.endbr_list);
-	file.ignore_unreachables = no_unreachable;
+	file.ignore_unreachables = opts.no_unreachable;
 	file.hints = false;
 
 	return &file;
@@ -137,7 +137,7 @@ struct objtool_file *objtool_open_read(const char *_objname)
 
 void objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
 {
-	if (!noinstr)
+	if (!opts.noinstr)
 		return;
 
 	if (!f->pv_ops) {