drivers: spi: mcux_flexcomm: Fix build failure
drivers: spi: mcux_flexcomm: Fix build failure

Change to spi_context_lock missed one spot in the flexcomm driver and
this causes a build issue.  Pass spi_cfg to spi_context_lock to fix
the issue.

Signed-off-by: Kumar Gala <a5e5248af4cd4f0ed8c515f61d40a6e2db46a66e@linaro.org>

finikorg/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,galak/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,Vudentz/zephyr,nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,finikorg/zephyr,finikorg/zephyr,nashif/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,Vudentz/zephyr