mkeficapsule: add FMP Payload Header

Current mkeficapsule tool does not provide firmware
version management. EDK II reference implementation inserts
the FMP Payload Header right before the payload.
It coutains the fw_version and lowest supported version.

This commit adds a new parameters required to generate
the FMP Payload Header for mkeficapsule tool.
 '-v' indicates the firmware version.

When mkeficapsule tool is invoked without '-v' option,
FMP Payload Header is not inserted, the behavior is same as
current implementation.

The lowest supported version included in the FMP Payload Header
is not used, the value stored in the device tree is used instead.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>