objtool: Shrink struct instruction

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2090231



commit c509331b
Author: Peter Zijlstra <peterz@infradead.org>
Date:   Tue, 26 Oct 2021 14:01:35 +0200

    objtool: Shrink struct instruction

    Any one instruction can only ever call a single function, therefore
    insn->mcount_loc_node is superfluous and can use insn->call_node.

    This shrinks struct instruction, which is by far the most numerous
    structure objtool creates.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
    Link: https://lore.kernel.org/r/20211026120309.785456706@infradead.org



Signed-off-by: Waiman Long <longman@redhat.com>