The -Wno-sometimes-uninitialized suppression seems to no longer be
necessary. Removing it as it may mask a real bug.
If the problem reappears, and if the comment is correct about it
being only in an unused function, then instead of adding the CFLAG,
it should be fixed locally via a patch.
Nimble contains a couple of casts that discard alignment information.
This causes a warning with clang's -Wno-address-of-packed-member.
A previous PR (#10503) supressed that warning. This commit re-enables
them and provides a patch to fix the offending code.
The fix has been submitted upstream, see
https://github.com/apache/mynewt-nimble/pull/252
When building `nimble` with LLVM/clang the function
`ble_ll_adv_active_chanset_is_sec()` in `ble_ll_adv.c` is reported to
be unused, it is used within an assertions and `ifdef`s within that
file though. So this just disables that warning.
