x86: edison: BINMAN selection is specific to the board

The platforms based on Intel Tangier may have different requirements
how to create bootloader bundle to supply to a device. Currently
the BINMAN approach is for Intel Edison only.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>