fix: generate sql incorrect when use soft_delete and only one OR

[ghost]

• [] Do only one thing
• [] Non breaking API changes
• [] Tested

What did this pull request do?

PR for #4914

• fix generate sql incorrect when use soft_delete and only one or
• 修复使用 soft_delete 并且仅有一个 or 时生成错误SQL.

User Case Description

Code:

func TestGORMorCondition(t *testing.T) {
	user := User{Name: "jinzhu"}
	DB.Create(&user)

	ret := make([]*User, 0)
	id := []uint32{1}
	db := DB
	for _, id := range id {
		db = db.Or("id = ?", id)
	}
	db.Find(&ret)
}

SQL:

[0.125ms] [rows:1] SELECT * FROM `users` WHERE id = 1 OR `users`.`deleted_at` IS NULL