Add support of kernel output both to connected monitor and UART
Add "usb start" at pre-boot stage to be able to use a keyboard in U-Boot

Fixes: https://github.com/OP-TEE/optee_os/issues/1367
https://github.com/OP-TEE/build/issues/131



Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
Signed-off-by: Igor Opaniuk <igor.opaniuk@linaro.org>

U-boot dhcp/bootp client changes "serverip" variable value in case if it
was specified in a dhcp/bootp server configuration.
Renamed serverip var, which now is used for nfsboot target to avoid
updating of this value by DHCP/BOOTP clients and just to use our
pre-defined static value.

Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
Tested-by: Joakim Bech <joakim.bech@linaro.org> (RPi3)
Signed-off-by: Igor Opaniuk <igor.opaniuk@linaro.org>

Add runtime kernel comandline creation (for both mmc/nfs boot)

Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
Signed-off-by: Igor Opaniuk <igor.opaniuk@linaro.org>
Tested-by: Igor Opaniuk <igor.opaniuk@linaro.org>

Add support for generation of uboot.env image from txt file

Fixes: https://github.com/OP-TEE/build/issues/85


Signed-off-by: Igor Opaniuk <igor.opaniuk@linaro.org>
Tested-by: Igor Opaniuk <igor.opaniuk@linaro.org> (RPi3)
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>