This commit removes definitions of CONFIG_SYS_BARGSIZE defined to be
equal to CONFIG_SYS_CBSIZE in numerous configuration files.

We remove such definitions in two situations:

 - CONFIG_SYS_CBSIZE is otherwise not defined in the board
   configuration file, which means the default value of
   CONFIG_SYS_CBSIZE == 256 applies. In this case, the default value
   of CONFIG_SYS_BARGSIZE == 512 (common/image.c) is suitable, as it is
   larger.

 - CONFIG_SYS_CBSIZE is defined in the board configuration file, but
   to a value equal or less than 512. In this case, the default value
   of CONFIG_SYS_BARGSIZE == 512 (common.image.c) is suitable, as it
   is equal or larger.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Tom Rini <trini@konsulko.com>