defconfigs: am335x_hs_evm: Sync HS and non-HS defconfigs

Sync new additions to non-HS defconfig with HS defconfig. Also add SPL
NAND support, this was disabled before due to size constraints, enable
this now at the expense of the less used GPT partition support.

Signed-off-by: Andrew F. Davis <afd@ti.com>