drivers: spi_dw: remove unused LOG_DOMAIN define
drivers: spi_dw: remove unused LOG_DOMAIN define

This define for the log domain in obsolete and not being used.

Signed-off-by: Anas Nashif <0d9952ec84ac43c159f6b7e7ed99a9080c00dd6e@intel.com>

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