KNF. Remove ( ) from return statements.
Use int for return type for [eou]chi_init and motg_init.
Remove unnecessary needs-flags against the usb attribute.
KNF. Remove argument name from function declarations.

No functional change.
Use c99 designated initialisers for ucom_methods structs.

No functional change.
Fix pasto that meant kmem_free was called twice against sc_statusbuf. Free
sc_status instead.
Set ub_usedma to false.