Remove the assert on alignment check.
Remove the assert on alignment check.

Also the alignment should only be done on general register types as
per the AAPCS so fixed that issue.

Copyright (c) 2020, Arm Limited.

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust