configs: imx: Make CONFIG_SYS_PROMPT uniform across FSL boards

There is no real benefit in adding the board name into U-boot's prompt, so
remove the custom CONFIG_SYS_PROMPT definitions so that the standard "=> "
prompt is used across FSL boards.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
10 files changed