AM3517 CraneBoard: Add SPL support

The only change of note is that we move from 0x80008000 to 0x80100000
for CONFIG_SYS_TEXT_BASE

Cc: Nagendra T S <nagendra@mistralsolutions.com>
Tested-by: Koen Kooi <k-kooi@ti.com>
Signed-off-by: Tom Rini <trini@ti.com>