distinguish between schema.Time and tag time

[black-06]

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

What did this pull request do?

fix go-gorm/gorm#6033

User Case Description

type Test struct {
    Date time.Time `gorm:"type:date"`
    Time time.Time `gorm:"type:time"`
    DefaultDateTime time.Time
}

CREATE TABLE `tests` (`date` date,`time` time,`default_date_time` datetime)