stm32mp: stm32prog: add FIP header support

Add support of TF-A FIP header in command stm32prog for all the boot
partition and not only the STM32IMAGE.

This patch is a preliminary patch to support FIP as second boot stage
after TF-A BL2 when CONFIG_TFABOOT is activated for trusted boot chain.

The FIP is archive binary loaded by TF-A BL2, which contains the secure OS
= OP-TEE and the non secure firmware and device tree = U-Boot.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>