I am using SPI 2 (not SPIM) and just migrated my project to SDK14 from 13.1.
I kept getting "Wrong configuration" on compile, until I realized that on the nrf_srv_spi.c on the #defines you replicated SPI1_WITHOUT_DMA twice on line 81. Easy fix is to change the second one to SPI2_WITHOUT_DMA.
I hope this helps someone.
Thanks!