imx6: move generic imx6 options to mx6_common.h

All boards define CONFIG_MX6, CONFIG_DISPLAY_BOARDINFO, CONFIG_DISPLAY_CPUINFO
and CONFIG_SYS_GENERIC_BOARD so define them in mx6_common

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Tom Rini <trini at konsulko.com>
24 files changed