media: ti-vpe: cal: Name all cal_dev pointers consistently
Name all variables pointing to a cal_dev instance 'cal', instead of a
combination of 'caldev' and 'dev'. 'caldev' is only used in a few places
and could have been renamed to 'dev', but 'dev' is confusing as it's
also used for struct device instances. This generates lots of changes,
but increases readability.