ddr: imx8ulp: Change DRAM timing save area to 0x20055000

To align with ARM trusted firmware's change, adjust DRAM timing
save area to new position 0x20055000. So we can release the space
since 0x2006c000 for the NOBITS region of ARM trusted firmware

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Jacky Bai <ping.bai@nxp.com>

drivers/ddr/imx/imx8ulp/Kconfig

@@ -13,6 +13,6 @@ config SAVED_DRAM_TIMING_BASE
 	help
 	  The DRAM config timing data need to be saved into sram
 	  for low power use.
-	default 0x2006c000
+	default 0x20055000
 
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