struct_assignment: remove bogus deref_expression()

Originally this handled both "ptr = ptr" and "struct = struct", but now
it converts "ptr = ptr" to struct = struct.  The is_pointer() check was
left over from the old code and can be deleted.

I noticed this bug during review.  It's possible the bug fix has some small
effect on run time.

Signed-off-by: Dan Carpenter <[email protected]>

Author: Dan Carpenter

smatch_struct_assignment.c

@@ -104,9 +104,6 @@ static struct expression *get_right_base_expr(struct symbol *left_type, struct e
 	if (right->type == EXPR_CALL)
 		return NULL;
 
-	if (is_pointer(right))
-		right = deref_expression(right);
-
 	return right;
 }