ARM: at91/defconfig: refresh at91sam9rl_defconfig

The defconfig for the at91sam9rl is quite old, refresh it:
 - now uses EABI instead of OABI
 - add devtmpfs support
 - add UBI/UBIfs support
 - remove a few config symbols that disappeared

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>