spi: Remove unused Kconfig symbols from mcux dspi driver
spi: Remove unused Kconfig symbols from mcux dspi driver

These mcux dspi driver configs are no longer used after legacy API
support was removed in commit 09dd5e9b2207c0ffabc16f0308ab0036b18bd3a6.

Signed-off-by: Maureen Helm <87a696db5547fa477bda9f9e0f00013c839c14d3@nxp.com>

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