teensy40: remove FPU spec in target JSON list of cflags

src/machine/uart.go

@@ -1,4 +1,4 @@
-// +build avr esp nrf sam sifive stm32 k210 nxp,!mimxrt1062
+// +build avr esp nrf sam sifive stm32 k210 nxpmk66f18
 
 package machine
 

targets/teensy40.json

@@ -9,7 +9,6 @@
     "--target=armv7em-none-eabi",
     "-Qunused-arguments",
     "-mfloat-abi=soft",
-    "-mfpu=fpv5-d16"
   ],
   "linkerscript": "targets/mimxrt1062-teensy40.ld",
   "extra-files": [