arm: dts: k3: binman: am62a: add support for signing TIFSStub Images

Add support for signing of TIFSSTUB images for HSSE, HSFS and GP devices
and include them in tispl.bin and tispl.bin_unsigned.

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: Vibhore Vardhan <vibhore@ti.com>
Signed-off-by: Dhruva Gole <d-gole@ti.com>