TQM5200: fix bug in SDRAM initialization code

This patch fixes a bug in the SDRAM initialization code for the
TQM5200. The hi_addr bit is now set correctly. Without this patch
the hi_addr bit is always set to 1, if the second SDRAM bank is
not populated.

For other MPC5200 boards a correspondig patch has already been applied
some time ago, see commit a6310928.

Signed-off-by: Martin Krause <martin.krause@tqs.de>
--
Forget the first patch please. I confused flash with SDRAM in
the comment ...