AutoMigrate failed when type has custom size or precision

## GORM Playground Link

```
type Product struct {
Price float64 `gorm:"type:decimal(10,2);not null"`
}

...

DB.AutoMigrate(Product{})
```

## Description
The database is initialized normally for the first time, but it crashes after restarting the application, returning the error `invaild DDL, unbalanced brackets`

According to my repeated debugging, the problem appears in `migrate.go`
At line 89, it would replace `decimal (10,2)` to `?, 2)`