Correct typo in line meant to turn off frequencyio on M0 which saves 2k code space.

tannewt · tannewt · commit cdfc169ab67d · 2019-07-19T16:10:32.000-07:00
diff --git a/ports/atmel-samd/mpconfigport.mk b/ports/atmel-samd/mpconfigport.mk
@@ -17,7 +17,7 @@ endif
 # Put samd21-only choices here.
 ifeq ($(CHIP_FAMILY),samd21)
 # frequencyio not yet verified as working on SAMD21.
-CIRCUITPY_FRQUENCYIO = 0
+CIRCUITPY_FREQUENCYIO = 0
 endif
 
 # Put samd51-only choices here.
