uboot-imx

tools: image: fix "algo" property of public key for verified boot

The "algo_name" points to a property in a blob being edited.  The
pointer becomes stale when fit_image_write_sig() inserts signatures.
Then crypto->add_verify_data() writes wrong data to the public key
destination.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>