board: ti: am64x: Recognize AM64-HSEVM

AM64-HSEVM is AM64-GPEVM with High Security Device.

Gets rid of "Unidentified board claims AM64-HSEVM in eeprom header".

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Acked-by: Andrew Davis <afd@ti.com>
Reviewed-by: Nishanth Menon <nm@ti.com>
Tested-by: Nishanth Menon <nm@ti.com> #SK-AM64B