nimble/ll: Check peer features for LE Connection Update
nimble/ll: Check peer features for LE Connection Update

We should use Connection Parameters Request procedure only if both
master and slave support this feature so we need to check features
masks of both sides.

In other case, we can do Connection Update procedure only if we're
master.

X-Original-Commit: 80793bf6e36e13953fce18950929af5e91867d12

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