mem: Tidy up Request
mem: Tidy up Request

This patch does a bit of house keeping, fixing up typos, removing dead
code etc.
(transplanted from dcd7cf19f7c5592036c80c3d7b6e531641494292)

andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin