avoid casting pointer arguments to argconfig functions

avoid casting pointer arguments to argconfig functions

Same issue as 456a24e8daa7e0cccddfef7deaffe7b200358706 ("Don't cast
pointers, cast values."), which was undone in
18de3a6d61a7f090ecea9f6afa52c2d6591d1700 ("Convert to libnvme").

Add some functions to argconfig so that we can directly pass in
__u16/__u32/__u64 arrays without casting to int/long/etc, since an int
isn't always 32 bits, an unsigned long long isn't always 64 bits, etc.

Suggested-by: Randy Jennings <randyj@purestorage.com>