Fix AMCC Sequoia board DDR memory configuration

Fix AMCC Sequoia board DDR memory configuration

Sequoia board schematics (DES0211_11_SCH_11.pdf, page 5, unit U1D)
specifies that BankSel#1 is not connected, while bootloader memory
configuration is (board/amcc/sequoia/sdram.c):
       mtsdram(DDR0_10, 0x00000300);
i.e. both Chip Selects used - not correct.

If we change to correct value here:
       mtsdram(DDR0_10, 0x00000100);
memory is accessible OK also.

Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
Signed-off-by: Stefan Roese <sr@denx.de>