nimble/host: Fix invalid symbol name
nimble/host: Fix invalid symbol name

This can be considered API change but the symbol name is obviously
invalid as it does not follow naming scheme so let's change it anyway.

X-Original-Commit: ea901abcdf35a2ca433bf7624956b02b0839d730

apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble