arm: dts: k3-am625-verdin: add tifsstub to tispl.bin

Adds tifsstub binaries, this is required for deepsleep functionality.

This implements the same change as commit 128f8129 ("arm: dts: k3:
binman: am625: add support for signing TIFSSTUB Images") did for TI AM62
SK board.

Signed-off-by: Parth Pancholi <parth.pancholi@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>