staging: fsl-mc: Add new flags field to MC command header

The Management Complex (MC) binary interface added a new "flags"
field to the command header.
Add the definitions for this field in preparation for adding the
new cmd_flags parameter to all MC interface APIs.

Signed-off-by: J. German Rivera <German.Rivera@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>