stm32: common: fix missing SPI_I2S_BASE rename regression

Fix regresion from 5d4437fe43aa68a28611e9a0aecc712833230304 where
somehow not all occurrences were replaced.  I could swear it all
compiled when I was working on it :(

Reported-by: Trevor Woerner <trevor.woerner@linaro.org>
Merge remote-tracking branch 'upstream/master'