common: drop CONFIG_SYS_RESET_ADDR

There are no boards that define CONFIG_SYS_RESET_ADDR, so drop the
remaining comments referencing it and also the config_whitelist.txt entry.

Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Acked-by:  <thomas@wytron.com.tw>