README: modify README
README: modify README

- fix trivial typo
- remove unofficial config info

Change-Id: I791f8b4723b3a1b8b175a8f8c7e288e4642ee87f
Signed-off-by: Junhwan Park <7fee488b6f78fc50b291ffc7d10428788977e877@samsung.com>

JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT