arm: Correct CONFIG_STANDALONE_LOAD_ADDR for AM33XX/OMAP* platforms

All of these platforms have memory starting at 0x80000000, so this is
the correct CONFIG_STANDALONE_LOAD_ADDR for all of them.

Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Tom Rini <trini@ti.com>