Update features definitions and configurations. Now atxmega define
features that only are full available on all variations and do not
require any definition at periph_conf.h file.
Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>
The periph_pm requires new field to control the power management
feature. Add missing config at periph_conf for timers and uart.
Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>
