nitrogen6_max: include CMD_FS_GENERIC

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
nitrogen6_max: skip filesystem loop with CONFIG_FS_GENERIC

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
nitrogen6_max: expose SATA, then MMC over USB

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
nitrogen6x: expose SATA, then MMC over USB

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
nit6xlite: configure bootcmd/upgradeu to allow USB, use generic load

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
nit6xlite: expose SD card over USB

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>