dts: intel_s1000: update SRAM size to 4MB
dts: intel_s1000: update SRAM size to 4MB

Intel S1000 has 4MB of internal memory.
In DTS it was defined as 3MB and is now updated to 4MB.

Signed-off-by: Sathish Kuttan <88b3ab91bbfd8c103d682ea5f9059cf275a3b834@intel.com>

punitvara/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,finikorg/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,finikorg/zephyr,Vudentz/zephyr,galak/zephyr,ldts/zephyr,ldts/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,punitvara/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,punitvara/zephyr,ldts/zephyr,nashif/zephyr,ldts/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,explora26/zephyr,galak/zephyr,punitvara/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,explora26/zephyr,galak/zephyr,finikorg/zephyr