arm, davinci: Fix setting of the SDRAM configuration register

arm, davinci: Fix setting of the SDRAM configuration register

da850_ddr_setup() expects the BOOTUNLOCK bit to be set in
If BOOTUNLOCK is not set in this define, several configuration
bits will not be writeable and the code will not work.

Since the BOOTUNLOCK and TIMUNLOCK bits are not configuration options
but access control bits, this patch changes the code to work
irrespective of the value of these bits in CONFIG_SYS_DA850_DDR2_SDBCR.

Signed-off-by: Christian Riesch <christian.riesch@omicron.at>
Cc: Heiko Schocher <hs@denx.de>
Cc: Paulraj Sandeep <s-paulraj@ti.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>