Removing use of undefined TASKS_START behavior
Removing use of undefined TASKS_START behavior

Tested using the bleprph app. The problem was that the behavior of the RNG TASKS_START is defined to be write only. Reading from it is undefined and though it might have worked up until now doesn't mean it'll constantly work. I was only able to catch on to this using an emulator.

X-Original-Commit: fc0da53f8abedb1c7fce4e35ee565e310e971fdb

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