The following commits added commandline arguments to control following the Arm
Procedure Call Standard for certain volatile bitfield operations:
This commit fixes the oversight that these args weren't passed from the driver
to cc1 if appropriate.
Where *appropriate* means:
- -faapcs-bitfield-width: is the default, so won't be passed
- -fno-aapcs-bitfield-width: should be passed
- -faapcs-bitfield-load: should be passed